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Bazinga Merge #9

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flar2 and others added 30 commits June 24, 2016 00:56
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Changes:
--------
v4->v3:
- s/random_stack_user()/get_atrandom_bytes()/
- Move this function to ahead of its use to avoid the predeclaration.

v3->v2:
- Tweak code comments of random_stack_user().
- Remove redundant bits mask and shift upon the random variable.

v2->v1:
- Fix random copy to check up buffer length that are not 4-byte multiples.

v3 can be found at:
http://www.spinics.net/lists/linux-fsdevel/msg59597.html
v2 can be found at:
http://www.spinics.net/lists/linux-fsdevel/msg59418.html
v1 can be found at:
http://www.spinics.net/lists/linux-fsdevel/msg59128.html

Thanks,
-Jeff

Entropy is quickly depleted under normal operations like ls(1), cat(1),
etc...  between 2.6.30 to current mainline, for instance:

$ cat /proc/sys/kernel/random/entropy_avail
3428
$ cat /proc/sys/kernel/random/entropy_avail
2911
$cat /proc/sys/kernel/random/entropy_avail
2620

We observed this problem has been occurring since 2.6.30 with
fs/binfmt_elf.c: create_elf_tables()->get_random_bytes(), introduced by
f06295b ("ELF: implement AT_RANDOM for glibc PRNG seeding").

/*
 * Generate 16 random bytes for userspace PRNG seeding.
 */
get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));

The patch introduces a wrapper around get_random_int() which has lower
overhead than calling get_random_bytes() directly.

With this patch applied:
$ cat /proc/sys/kernel/random/entropy_avail
2731
$ cat /proc/sys/kernel/random/entropy_avail
2802
$ cat /proc/sys/kernel/random/entropy_avail
2878

Analyzed by John Sobecki.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <aedilger@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnn@arndb.de>
Cc: John Sobecki <john.sobecki@oracle.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Running mmcqd as a prio 120 thread forces it to compete with standard
user processes for IO performance, especially when the system is under
severe CPU load. Move it to a SCHED_FIFO thread to reduce the impact of
load on IO performance.

bug 25392275

Change-Id: I1edfe73baa25e181367c30c1f40fee886e92b60d

Signed-off-by: flar2 <asegaert@gmail.com>
Running dm-verity in a standard workqueue results in IO competing for
CPU time with standard user apps, which can lead to pipeline bubbles and
seriously degraded performance. Move to a WQ_HIGHPRI workqueue to
protect against that.

bug 25392275

Change-Id: Ic65d7bd6f04e4d77780119e926a50e71323575f0

Signed-off-by: flar2 <asegaert@gmail.com>
Running dm-crypt in a standard workqueue results in IO competing for CPU
time with standard user apps, which can lead to pipeline bubbles and
seriously degraded performance. Move to a WQ_HIGHPRI workqueue to
protect against that.

bug 25392275

Change-Id: I589149a31c7b5d322fe2ed5b2476b1f6e3d5ee6f

Signed-off-by: flar2 <asegaert@gmail.com>
When compiling the kernel with  the compiler
"aarch64-linux-android-gcc (GCC) 4.9.x-google 20140827 (prerelease)"
The compiler seems to be optimizing a value out in the do_sync_write
function and is incorrectly passing the pointer instead of the
dereferenced value.
Force the compiler to use the right value by passing the dereferenced
pointer instead of another variable that is assigned with the dereferenced
value.

Change-Id: I60505ffe39393f6323dcc7c6f912c74ea6aca6cd
Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>
This patch fixes a bug in CUBIC that causes cwnd to increase slightly
too slowly when multiple ACKs arrive in the same jiffy.

If cwnd is supposed to increase at a rate of more than once per jiffy,
then CUBIC was sometimes too slow. Because the bic_target is
calculated for a future point in time, calculated with time in
jiffies, the cwnd can increase over the course of the jiffy while the
bic_target calculated as the proper CUBIC cwnd at time
t=tcp_time_stamp+rtt does not increase, because tcp_time_stamp only
increases on jiffy tick boundaries.

So since the cnt is set to:
	ca->cnt = cwnd / (bic_target - cwnd);
as cwnd increases but bic_target does not increase due to jiffy
granularity, the cnt becomes too large, causing cwnd to increase
too slowly.

For example:
- suppose at the beginning of a jiffy, cwnd=40, bic_target=44
- so CUBIC sets:
   ca->cnt =  cwnd / (bic_target - cwnd) = 40 / (44 - 40) = 40/4 = 10
- suppose we get 10 acks, each for 1 segment, so tcp_cong_avoid_ai()
   increases cwnd to 41
- so CUBIC sets:
   ca->cnt =  cwnd / (bic_target - cwnd) = 41 / (44 - 41) = 41 / 3 = 13

So now CUBIC will wait for 13 packets to be ACKed before increasing
cwnd to 42, insted of 10 as it should.

The fix is to avoid adjusting the slope (determined by ca->cnt)
multiple times within a jiffy, and instead skip to compute the Reno
cwnd, the "TCP friendliness" code path.

Reported-by: Eyal Perry <eyalpe@mellanox.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Jana Iyengar found an interesting issue on CUBIC :

The epoch is only updated/reset initially and when experiencing losses.
The delta "t" of now - epoch_start can be arbitrary large after app idle
as well as the bic_target. Consequentially the slope (inverse of
ca->cnt) would be really large, and eventually ca->cnt would be
lower-bounded in the end to 2 to have delayed-ACK slow-start behavior.

This particularly shows up when slow_start_after_idle is disabled
as a dangerous cwnd inflation (1.5 x RTT) after few seconds of idle
time.

Jana initial fix was to reset epoch_start if app limited,
but Neal pointed out it would ask the CUBIC algorithm to recalculate the
curve so that we again start growing steeply upward from where cwnd is
now (as CUBIC does just after a loss). Ideally we'd want the cwnd growth
curve to be the same shape, just shifted later in time by the amount of
the idle period.

Change-Id: Ia99e2743517729b1c0589fbb8db9965ec806043b
Reported-by: Jana Iyengar <jri@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Sangtae Ha <sangtae.ha@gmail.com>
Cc: Lawrence Brakmo <lawrence@brakmo.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tracking idle time in bictcp_cwnd_event() is imprecise, as epoch_start
is normally set at ACK processing time, not at send time.

Doing a proper fix would need to add an additional state variable,
and does not seem worth the trouble, given CUBIC bug has been there
forever before Jana noticed it.

Let's simply not set epoch_start in the future, otherwise
bictcp_update() could overflow and CUBIC would again
grow cwnd too fast.

This was detected thanks to a packetdrill test Neal wrote that was flaky
before applying this fix.

Change-Id: I600d3a8ac0ed1d70f3ff5cc6b7341ac13178f4f3
Fixes: 3092752 ("tcp_cubic: better follow cubic curve after idle period")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Cc: Jana Iyengar <jri@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
To avoid locking and per-cpu overhead, SLUB optimisically uses
high-order allocations up to order-3 by default and falls back to
lower allocations if they fail. While care is taken that the caller
and kswapd take no unusual steps in response to this, there are
further consequences like shrinkers who have to free more objects to
release any memory. There is anecdotal evidence that significant time
is being spent looping in shrinkers with insufficient progress being
made (https://lkml.org/lkml/2011/4/28/361) and keeping kswapd awake.

SLUB is now the default allocator and some bug reports have been
pinned down to SLUB using high orders during operations like
copying large amounts of data. SLUBs use of high-orders benefits
applications that are sized to memory appropriately but this does not
necessarily apply to large file servers or desktops.  This patch
causes SLUB to use order-0 pages like SLAB does by default.
There is further evidence that this keeps kswapd's usage lower
(https://lkml.org/lkml/2011/5/10/383).

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Update Kconfig.iosched and do the related Makefile changes to include
kernel configuration options for BFQ. Also add the bfqio controller
to the cgroups subsystem.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Add the BFQ-v7r8 I/O scheduler to 3.18.0.
The general structure is borrowed from CFQ, as much of the code for
handling I/O contexts. Over time, several useful features have been
ported from CFQ as well (details in the changelog in README.BFQ). A
(bfq_)queue is associated to each task doing I/O on a device, and each
time a scheduling decision has to be made a queue is selected and served
until it expires.

    - Slices are given in the service domain: tasks are assigned
      budgets, measured in number of sectors. Once got the disk, a task
      must however consume its assigned budget within a configurable
      maximum time (by default, the maximum possible value of the
      budgets is automatically computed to comply with this timeout).
      This allows the desired latency vs "throughput boosting" tradeoff
      to be set.

    - Budgets are scheduled according to a variant of WF2Q+, implemented
      using an augmented rb-tree to take eligibility into account while
      preserving an O(log N) overall complexity.

    - A low-latency tunable is provided; if enabled, both interactive
      and soft real-time applications are guaranteed a very low latency.

    - Latency guarantees are preserved also in the presence of NCQ.

    - Also with flash-based devices, a high throughput is achieved
      while still preserving latency guarantees.

    - BFQ features Early Queue Merge (EQM), a sort of fusion of the
      cooperating-queue-merging and the preemption mechanisms present
      in CFQ. EQM is in fact a unified mechanism that tries to get a
      sequential read pattern, and hence a high throughput, with any
      set of processes performing interleaved I/O over a contiguous
      sequence of sectors.

    - BFQ supports full hierarchical scheduling, exporting a cgroups
      interface.  Since each node has a full scheduler, each group can
      be assigned its own weight.

    - If the cgroups interface is not used, only I/O priorities can be
      assigned to processes, with ioprio values mapped to weights
      with the relation weight = IOPRIO_BE_NR - ioprio.

    - ioprio classes are served in strict priority order, i.e., lower
      priority queues are not served as long as there are higher
      priority queues.  Among queues in the same class the bandwidth is
      distributed in proportion to the weight of each queue. A very
      thin extra bandwidth is however guaranteed to the Idle class, to
      prevent it from starving.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
A set of processes may happen  to  perform interleaved reads, i.e.,requests
whose union would give rise to a  sequential read  pattern.  There are two
typical  cases: in the first  case,   processes  read  fixed-size chunks of
data at a fixed distance from each other, while in the second case processes
may read variable-size chunks at  variable distances. The latter case occurs
for  example with  QEMU, which  splits the  I/O generated  by the  guest into
multiple chunks,  and lets these chunks  be served by a  pool of cooperating
processes,  iteratively  assigning  the  next  chunk of  I/O  to  the first
available  process. CFQ  uses actual  queue merging  for the  first type of
rocesses, whereas it  uses preemption to get a sequential  read pattern out
of the read requests  performed by the second type of  processes. In the end
it uses  two different  mechanisms to  achieve the  same goal: boosting the
throughput with interleaved I/O.

This patch introduces  Early Queue Merge (EQM), a unified mechanism to get a
sequential  read pattern  with both  types of  processes. The  main idea is
checking newly arrived requests against the next request of the active queue
both in case of actual request insert and in case of request merge. By doing
so, both the types of processes can be handled by just merging their queues.
EQM is  then simpler and  more compact than the  pair of mechanisms used in
CFQ.

Finally, EQM  also preserves the  typical low-latency properties of BFQ, by
properly restoring the weight-raising state of a queue when it gets back to
a non-merged state.

Signed-off-by: Mauro Andreolini <mauro.andreolini@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: flar2 <asegaert@gmail.com>
Modify the round_rate() callback function so that it selects
the nearest configured fmax frequency instead of the closest
possible supported frequency of the parent clock.  This ensures
that clk_round_rate() always returns power efficient frequencies
for 8996 CPU clocks.

Change-Id: Icc27ba64b9c8af74ee0f81443fea37c4564b9f94
CRs-Fixed: 981475
Signed-off-by: David Collins <collinsd@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Correct CE clock setting for crypto drivers, core_clk_src should
link to voting clock; otherwise, ce1 clock is set to be only half
of 171M HZ during crypto operations.

Change-Id: I0d9e048381a83d4788bf4f700d788137b59bd368
Signed-off-by: Zhen Kong <zkong@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Updated characterization has shown the need to modify
certain calibration settings for hardware blocks within
the CPU subsystem. Modify these values.

CRs-Fixed: 930377
Change-Id: I601802746224e2abb43fd0b3aedb09e049062adf
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
To minimize spinlock, the qce50 client is assumed that it can only issue
request to qce50 driver one at a time. After a request is issued to
qce50 from qcrypto. Without waiting for completion, other requests can
still be issued until the maximum limit of outstanding requests
in qce50 reaches.

To cut down the chance of udp socket receive buffer overflow the following
schemes are provided -
The number of bunched requests in qce50 is based on the data length of
the current request to cut down delay for smaller packets. In turn,
with smaller delay, the number of completed requests to process in
seq_response() completion function is less.

The scheduling of qcrypto requests are changed from least use to
round robin. This way, the distribution of requests to each engine
is more even. As the result, reordering of completed requests will
be less. Completed requests to handle in completion callback is less
at a time.

Change-Id: I723bac2f9427cddb5248101c9ac3f2b595ad0379
Acked-by: Che-Min Hsieh <cheminh@qti.qualcomm.com>
Signed-off-by: Sivanesan Rajapupathi <srajap@codeaurora.org>
Fix a few possible NULL pointer dereferences.

Change-Id: Idc992d61952fc125e2898e1fc84f9ffecf9be737
Signed-off-by: William Clark <wclark@codeaurora.org>
Allow dsi phy power off during idle power collapse for
nt35597 command mode panel on msm8996 target.

Change-Id: I5e1065be9c21c10f577b1f7fea08e11725c2c675
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>
The attributes are updated to generate non-negative residency values. The
numbers do not affect the residency values.

Mode	| Time Overhead	| Energy OverHead	| SS Power
WFI(C1)	| 60		| 15000			| 200.0000
FPC(C4)	| 180		| 39740			| 198.0000

Best Mode below 60 us is Active
Best Mode below 550 us in WFI
Best Mode above 550 us is FPC

Mode		| Total Time Overhead	| Energy OverHead	| SS Power
L2 CG(D1)	| 85			| 65000			| 195.0000
L2 GDHS(D3)	| 180 			| 89070			| 180.0000
L2 FPC(D4)	| 1000			| 441000		| 160.0000

Best Mode below 85us is Active
Best Mode below 550us is WFI
Best Mode below 11500us is GDHS
Best Mode above 11500us is FPC

Mode	| Total Time Overhead	| Energy OverHead	| SS Power
E1-M1	| 120			| 60000			| 192.0000
E3-M2	| 150			| 69000			| 160.0000
E4-M3	| 1200			| 1380000		| 72.0000

Best mode below 120 us is Active
Best mode above 11500us is FPC

Change-Id: I4ba5d1361d7a9ff72531c4921e2941c56e935484
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
Add support for FPC without psci for cpus in DT. This mode helps reduce the
latency associated with entering Fast Power collapse by not incurring the
latency of terminating in the PSCI driver in Secure EL1.

Change-Id: I1209b62d45d10b74bd36756c4ddefa137fb571a5
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
It does not make sense to run kgsl on high and devfreq on regular
priority.

Change-Id: Ie5e6c9353a4e1324a6a49278e5ad3638462f551c

Signed-off-by: flar2 <asegaert@gmail.com>
flar2 and others added 5 commits December 6, 2016 20:26
Another round of security patches
Measured latency within the kernel driver has been fluctuating between 2~7ms.
Elevating the workqueues has made it more consistently in the 2~4ms range.

alloc_ordered_workqueue() still makes the workqueue singlethreaded
(internal __WQ_ORDERED flag), so this commit only adds WQ_HIGHPRI additionally.

Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
cpuidle was disabled while entering suspend as part of commit
8651f97 in order to work around some
ACPI bugs. However, there's no reason to do this on modern
platforms. Leaving cpuidle enabled can result in improved power
consumption if dpm_resume_noirq runs for a significant time.

Change-Id: Ie182785b176f448698c0264eba554d1e315e8a06
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
NewEraCracker pushed a commit to NewEraCracker/android_kernel_oneplus_msm8996 that referenced this pull request Apr 20, 2017
commit 45caeaa5ac0b4b11784ac6f932c0ad4c6b67cda0 upstream.

As Eric Dumazet pointed out this also needs to be fixed in IPv6.
v2: Contains the IPv6 tcp/Ipv6 dccp patches as well.

We have seen a few incidents lately where a dst_enty has been freed
with a dangling TCP socket reference (sk->sk_dst_cache) pointing to that
dst_entry. If the conditions/timings are right a crash then ensues when the
freed dst_entry is referenced later on. A Common crashing back trace is:

 OnePlusOSS#8 [] page_fault at ffffffff8163e648
    [exception RIP: __tcp_ack_snd_check+74]
.
.
 OnePlusOSS#9 [] tcp_rcv_established at ffffffff81580b64
OnePlusOSS#10 [] tcp_v4_do_rcv at ffffffff8158b54a
OnePlusOSS#11 [] tcp_v4_rcv at ffffffff8158cd02
OnePlusOSS#12 [] ip_local_deliver_finish at ffffffff815668f4
OnePlusOSS#13 [] ip_local_deliver at ffffffff81566bd9
OnePlusOSS#14 [] ip_rcv_finish at ffffffff8156656d
OnePlusOSS#15 [] ip_rcv at ffffffff81566f06
OnePlusOSS#16 [] __netif_receive_skb_core at ffffffff8152b3a2
OnePlusOSS#17 [] __netif_receive_skb at ffffffff8152b608
OnePlusOSS#18 [] netif_receive_skb at ffffffff8152b690
OnePlusOSS#19 [] vmxnet3_rq_rx_complete at ffffffffa015eeaf [vmxnet3]
OnePlusOSS#20 [] vmxnet3_poll_rx_only at ffffffffa015f32a [vmxnet3]
OnePlusOSS#21 [] net_rx_action at ffffffff8152bac2
OnePlusOSS#22 [] __do_softirq at ffffffff81084b4f
OnePlusOSS#23 [] call_softirq at ffffffff8164845c
OnePlusOSS#24 [] do_softirq at ffffffff81016fc5
OnePlusOSS#25 [] irq_exit at ffffffff81084ee5
OnePlusOSS#26 [] do_IRQ at ffffffff81648ff8

Of course it may happen with other NIC drivers as well.

It's found the freed dst_entry here:

 224 static bool tcp_in_quickack_mode(struct sock *sk)↩
 225 {↩
 226 ▹       const struct inet_connection_sock *icsk = inet_csk(sk);↩
 227 ▹       const struct dst_entry *dst = __sk_dst_get(sk);↩
 228 ↩
 229 ▹       return (dst && dst_metric(dst, RTAX_QUICKACK)) ||↩
 230 ▹       ▹       (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);↩
 231 }↩

But there are other backtraces attributed to the same freed dst_entry in
netfilter code as well.

All the vmcores showed 2 significant clues:

- Remote hosts behind the default gateway had always been redirected to a
different gateway. A rtable/dst_entry will be added for that host. Making
more dst_entrys with lower reference counts. Making this more probable.

- All vmcores showed a postitive LockDroppedIcmps value, e.g:

LockDroppedIcmps                  267

A closer look at the tcp_v4_err() handler revealed that do_redirect() will run
regardless of whether user space has the socket locked. This can result in a
race condition where the same dst_entry cached in sk->sk_dst_entry can be
decremented twice for the same socket via:

do_redirect()->__sk_dst_check()-> dst_release().

Which leads to the dst_entry being prematurely freed with another socket
pointing to it via sk->sk_dst_cache and a subsequent crash.

To fix this skip do_redirect() if usespace has the socket locked. Instead let
the redirect take place later when user space does not have the socket
locked.

The dccp/IPv6 code is very similar in this respect, so fixing it there too.

As Eric Garver pointed out the following commit now invalidates routes. Which
can set the dst->obsolete flag so that ipv4_dst_check() returns null and
triggers the dst_release().

Fixes: ceb3320 ("ipv4: Kill routes during PMTU/redirect updates.")
Cc: Eric Garver <egarver@redhat.com>
Cc: Hannes Sowa <hsowa@redhat.com>
Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
NewEraCracker pushed a commit to NewEraCracker/android_kernel_oneplus_msm8996 that referenced this pull request Jul 13, 2017
commit 4dfce57db6354603641132fac3c887614e3ebe81 upstream.

There have been several reports over the years of NULL pointer
dereferences in xfs_trans_log_inode during xfs_fsr processes,
when the process is doing an fput and tearing down extents
on the temporary inode, something like:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
PID: 29439  TASK: ffff880550584fa0  CPU: 6   COMMAND: "xfs_fsr"
    [exception RIP: xfs_trans_log_inode+0x10]
 OnePlusOSS#9 [ffff8800a57bbbe0] xfs_bunmapi at ffffffffa037398e [xfs]
OnePlusOSS#10 [ffff8800a57bbce8] xfs_itruncate_extents at ffffffffa0391b29 [xfs]
OnePlusOSS#11 [ffff8800a57bbd88] xfs_inactive_truncate at ffffffffa0391d0c [xfs]
OnePlusOSS#12 [ffff8800a57bbdb8] xfs_inactive at ffffffffa0392508 [xfs]
OnePlusOSS#13 [ffff8800a57bbdd8] xfs_fs_evict_inode at ffffffffa035907e [xfs]
OnePlusOSS#14 [ffff8800a57bbe00] evict at ffffffff811e1b67
OnePlusOSS#15 [ffff8800a57bbe28] iput at ffffffff811e23a5
OnePlusOSS#16 [ffff8800a57bbe58] dentry_kill at ffffffff811dcfc8
OnePlusOSS#17 [ffff8800a57bbe88] dput at ffffffff811dd06c
OnePlusOSS#18 [ffff8800a57bbea8] __fput at ffffffff811c823b
OnePlusOSS#19 [ffff8800a57bbef0] ____fput at ffffffff811c846e
OnePlusOSS#20 [ffff8800a57bbf00] task_work_run at ffffffff81093b27
OnePlusOSS#21 [ffff8800a57bbf30] do_notify_resume at ffffffff81013b0c
OnePlusOSS#22 [ffff8800a57bbf50] int_signal at ffffffff8161405d

As it turns out, this is because the i_itemp pointer, along
with the d_ops pointer, has been overwritten with zeros
when we tear down the extents during truncate.  When the in-core
inode fork on the temporary inode used by xfs_fsr was originally
set up during the extent swap, we mistakenly looked at di_nextents
to determine whether all extents fit inline, but this misses extents
generated by speculative preallocation; we should be using if_bytes
instead.

This mistake corrupts the in-memory inode, and code in
xfs_iext_remove_inline eventually gets bad inputs, causing
it to memmove and memset incorrect ranges; this became apparent
because the two values in ifp->if_u2.if_inline_ext[1] contained
what should have been in d_ops and i_itemp; they were memmoved due
to incorrect array indexing and then the original locations
were zeroed with memset, again due to an array overrun.

Fix this by properly using i_df.if_bytes to determine the number
of extents, not di_nextents.

Thanks to dchinner for looking at this with me and spotting the
root cause.

[nborisov: backported to 4.4]

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
NewEraCracker pushed a commit to NewEraCracker/android_kernel_oneplus_msm8996 that referenced this pull request Jul 13, 2017
[ Upstream commit b4846fc3c8559649277e3e4e6b5cec5348a8d208 ]

Andrey reported a lockdep warning on non-initialized
spinlock:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.
 CPU: 1 PID: 4099 Comm: a.out Not tainted 4.12.0-rc6+ OnePlusOSS#9
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 Call Trace:
  __dump_stack lib/dump_stack.c:16
  dump_stack+0x292/0x395 lib/dump_stack.c:52
  register_lock_class+0x717/0x1aa0 kernel/locking/lockdep.c:755
  ? 0xffffffffa0000000
  __lock_acquire+0x269/0x3690 kernel/locking/lockdep.c:3255
  lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
  __raw_spin_lock_bh ./include/linux/spinlock_api_smp.h:135
  _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:175
  spin_lock_bh ./include/linux/spinlock.h:304
  ip_mc_clear_src+0x27/0x1e0 net/ipv4/igmp.c:2076
  igmpv3_clear_delrec+0xee/0x4f0 net/ipv4/igmp.c:1194
  ip_mc_destroy_dev+0x4e/0x190 net/ipv4/igmp.c:1736

We miss a spin_lock_init() in igmpv3_add_delrec(), probably
because previously we never use it on this code path. Since
we already unlink it from the global mc_tomb list, it is
probably safe not to acquire this spinlock here. It does not
harm to have it although, to avoid conditional locking.

Fixes: c38b7d327aaf ("igmp: acquire pmc lock for ip_mc_clear_src()")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Martinusbe referenced this pull request in GZR-Kernels/kernel_oneplus_msm8996 Jul 24, 2017
commit 45caeaa5ac0b4b11784ac6f932c0ad4c6b67cda0 upstream.

As Eric Dumazet pointed out this also needs to be fixed in IPv6.
v2: Contains the IPv6 tcp/Ipv6 dccp patches as well.

We have seen a few incidents lately where a dst_enty has been freed
with a dangling TCP socket reference (sk->sk_dst_cache) pointing to that
dst_entry. If the conditions/timings are right a crash then ensues when the
freed dst_entry is referenced later on. A Common crashing back trace is:

 #8 [] page_fault at ffffffff8163e648
    [exception RIP: __tcp_ack_snd_check+74]
.
.
 #9 [] tcp_rcv_established at ffffffff81580b64
#10 [] tcp_v4_do_rcv at ffffffff8158b54a
#11 [] tcp_v4_rcv at ffffffff8158cd02
#12 [] ip_local_deliver_finish at ffffffff815668f4
#13 [] ip_local_deliver at ffffffff81566bd9
#14 [] ip_rcv_finish at ffffffff8156656d
#15 [] ip_rcv at ffffffff81566f06
#16 [] __netif_receive_skb_core at ffffffff8152b3a2
#17 [] __netif_receive_skb at ffffffff8152b608
#18 [] netif_receive_skb at ffffffff8152b690
#19 [] vmxnet3_rq_rx_complete at ffffffffa015eeaf [vmxnet3]
#20 [] vmxnet3_poll_rx_only at ffffffffa015f32a [vmxnet3]
#21 [] net_rx_action at ffffffff8152bac2
#22 [] __do_softirq at ffffffff81084b4f
#23 [] call_softirq at ffffffff8164845c
#24 [] do_softirq at ffffffff81016fc5
#25 [] irq_exit at ffffffff81084ee5
#26 [] do_IRQ at ffffffff81648ff8

Of course it may happen with other NIC drivers as well.

It's found the freed dst_entry here:

 224 static bool tcp_in_quickack_mode(struct sock *sk)↩
 225 {↩
 226 ▹       const struct inet_connection_sock *icsk = inet_csk(sk);↩
 227 ▹       const struct dst_entry *dst = __sk_dst_get(sk);↩
 228 ↩
 229 ▹       return (dst && dst_metric(dst, RTAX_QUICKACK)) ||↩
 230 ▹       ▹       (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);↩
 231 }↩

But there are other backtraces attributed to the same freed dst_entry in
netfilter code as well.

All the vmcores showed 2 significant clues:

- Remote hosts behind the default gateway had always been redirected to a
different gateway. A rtable/dst_entry will be added for that host. Making
more dst_entrys with lower reference counts. Making this more probable.

- All vmcores showed a postitive LockDroppedIcmps value, e.g:

LockDroppedIcmps                  267

A closer look at the tcp_v4_err() handler revealed that do_redirect() will run
regardless of whether user space has the socket locked. This can result in a
race condition where the same dst_entry cached in sk->sk_dst_entry can be
decremented twice for the same socket via:

do_redirect()->__sk_dst_check()-> dst_release().

Which leads to the dst_entry being prematurely freed with another socket
pointing to it via sk->sk_dst_cache and a subsequent crash.

To fix this skip do_redirect() if usespace has the socket locked. Instead let
the redirect take place later when user space does not have the socket
locked.

The dccp/IPv6 code is very similar in this respect, so fixing it there too.

As Eric Garver pointed out the following commit now invalidates routes. Which
can set the dst->obsolete flag so that ipv4_dst_check() returns null and
triggers the dst_release().

Fixes: ceb3320 ("ipv4: Kill routes during PMTU/redirect updates.")
Cc: Eric Garver <egarver@redhat.com>
Cc: Hannes Sowa <hsowa@redhat.com>
Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Martinusbe <martinusbe@gmail.com>
Martinusbe referenced this pull request in GZR-Kernels/kernel_oneplus_msm8996 Jul 24, 2017
commit 4dfce57db6354603641132fac3c887614e3ebe81 upstream.

There have been several reports over the years of NULL pointer
dereferences in xfs_trans_log_inode during xfs_fsr processes,
when the process is doing an fput and tearing down extents
on the temporary inode, something like:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
PID: 29439  TASK: ffff880550584fa0  CPU: 6   COMMAND: "xfs_fsr"
    [exception RIP: xfs_trans_log_inode+0x10]
 #9 [ffff8800a57bbbe0] xfs_bunmapi at ffffffffa037398e [xfs]
#10 [ffff8800a57bbce8] xfs_itruncate_extents at ffffffffa0391b29 [xfs]
#11 [ffff8800a57bbd88] xfs_inactive_truncate at ffffffffa0391d0c [xfs]
#12 [ffff8800a57bbdb8] xfs_inactive at ffffffffa0392508 [xfs]
#13 [ffff8800a57bbdd8] xfs_fs_evict_inode at ffffffffa035907e [xfs]
#14 [ffff8800a57bbe00] evict at ffffffff811e1b67
#15 [ffff8800a57bbe28] iput at ffffffff811e23a5
#16 [ffff8800a57bbe58] dentry_kill at ffffffff811dcfc8
#17 [ffff8800a57bbe88] dput at ffffffff811dd06c
#18 [ffff8800a57bbea8] __fput at ffffffff811c823b
#19 [ffff8800a57bbef0] ____fput at ffffffff811c846e
#20 [ffff8800a57bbf00] task_work_run at ffffffff81093b27
#21 [ffff8800a57bbf30] do_notify_resume at ffffffff81013b0c
#22 [ffff8800a57bbf50] int_signal at ffffffff8161405d

As it turns out, this is because the i_itemp pointer, along
with the d_ops pointer, has been overwritten with zeros
when we tear down the extents during truncate.  When the in-core
inode fork on the temporary inode used by xfs_fsr was originally
set up during the extent swap, we mistakenly looked at di_nextents
to determine whether all extents fit inline, but this misses extents
generated by speculative preallocation; we should be using if_bytes
instead.

This mistake corrupts the in-memory inode, and code in
xfs_iext_remove_inline eventually gets bad inputs, causing
it to memmove and memset incorrect ranges; this became apparent
because the two values in ifp->if_u2.if_inline_ext[1] contained
what should have been in d_ops and i_itemp; they were memmoved due
to incorrect array indexing and then the original locations
were zeroed with memset, again due to an array overrun.

Fix this by properly using i_df.if_bytes to determine the number
of extents, not di_nextents.

Thanks to dchinner for looking at this with me and spotting the
root cause.

[nborisov: backported to 4.4]

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Martinusbe <martinusbe@gmail.com>
Martinusbe referenced this pull request in GZR-Kernels/kernel_oneplus_msm8996 Jul 24, 2017
[ Upstream commit b4846fc3c8559649277e3e4e6b5cec5348a8d208 ]

Andrey reported a lockdep warning on non-initialized
spinlock:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.
 CPU: 1 PID: 4099 Comm: a.out Not tainted 4.12.0-rc6+ #9
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 Call Trace:
  __dump_stack lib/dump_stack.c:16
  dump_stack+0x292/0x395 lib/dump_stack.c:52
  register_lock_class+0x717/0x1aa0 kernel/locking/lockdep.c:755
  ? 0xffffffffa0000000
  __lock_acquire+0x269/0x3690 kernel/locking/lockdep.c:3255
  lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
  __raw_spin_lock_bh ./include/linux/spinlock_api_smp.h:135
  _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:175
  spin_lock_bh ./include/linux/spinlock.h:304
  ip_mc_clear_src+0x27/0x1e0 net/ipv4/igmp.c:2076
  igmpv3_clear_delrec+0xee/0x4f0 net/ipv4/igmp.c:1194
  ip_mc_destroy_dev+0x4e/0x190 net/ipv4/igmp.c:1736

We miss a spin_lock_init() in igmpv3_add_delrec(), probably
because previously we never use it on this code path. Since
we already unlink it from the global mc_tomb list, it is
probably safe not to acquire this spinlock here. It does not
harm to have it although, to avoid conditional locking.

Fixes: c38b7d327aaf ("igmp: acquire pmc lock for ip_mc_clear_src()")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martinusbe <martinusbe@gmail.com>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Jan 22, 2018
[ Upstream commit 76b8db0d480e8045e1a1902fc9ab143b3b9ef115 ]

On some platforms(e.g. rk3399 board), we can call hcd_add/remove
consecutively without calling usb_put_hcd/usb_create_hcd in between,
so hcd->flags can be stale.

If the HC dies due to whatever reason then without this patch we get
the below error on next hcd_add.

[173.296154] xhci-hcd xhci-hcd.2.auto: HC died; cleaning up
[173.296209] xhci-hcd xhci-hcd.2.auto: xHCI Host Controller
[173.296762] xhci-hcd xhci-hcd.2.auto: new USB bus registered, assigned bus number 6
[173.296931] usb usb6: We don't know the algorithms for LPM for this host, disabling LPM.
[173.297179] usb usb6: New USB device found, idVendor=1d6b, idProduct=0003
[173.297203] usb usb6: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[173.297222] usb usb6: Product: xHCI Host Controller
[173.297240] usb usb6: Manufacturer: Linux 4.4.21 xhci-hcd
[173.297257] usb usb6: SerialNumber: xhci-hcd.2.auto
[173.298680] hub 6-0:1.0: USB hub found
[173.298749] hub 6-0:1.0: 1 port detected
[173.299382] rockchip-dwc3 usb@fe800000: USB HOST connected
[173.395418] hub 5-0:1.0: activate --> -19
[173.603447] irq 228: nobody cared (try booting with the "irqpoll" option)
[173.603493] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.21 OnePlusOSS#9
[173.603513] Hardware name: Google Kevin (DT)
[173.603531] Call trace:
[173.603568] [<ffffffc0002087dc>] dump_backtrace+0x0/0x160
[173.603596] [<ffffffc00020895c>] show_stack+0x20/0x28
[173.603623] [<ffffffc0004b28a8>] dump_stack+0x90/0xb0
[173.603650] [<ffffffc00027347c>] __report_bad_irq+0x48/0xe8
[173.603674] [<ffffffc0002737cc>] note_interrupt+0x1e8/0x28c
[173.603698] [<ffffffc000270a38>] handle_irq_event_percpu+0x1d4/0x25c
[173.603722] [<ffffffc000270b0c>] handle_irq_event+0x4c/0x7c
[173.603748] [<ffffffc00027456c>] handle_fasteoi_irq+0xb4/0x124
[173.603777] [<ffffffc00026fe3c>] generic_handle_irq+0x30/0x44
[173.603804] [<ffffffc0002701a8>] __handle_domain_irq+0x90/0xbc
[173.603827] [<ffffffc0002006f4>] gic_handle_irq+0xcc/0x188
...
[173.604500] [<ffffffc000203700>] el1_irq+0x80/0xf8
[173.604530] [<ffffffc000261388>] cpu_startup_entry+0x38/0x3cc
[173.604558] [<ffffffc00090f7d8>] rest_init+0x8c/0x94
[173.604585] [<ffffffc000e009ac>] start_kernel+0x3d0/0x3fc
[173.604607] [<0000000000b16000>] 0xb16000
[173.604622] handlers:
[173.604648] [<ffffffc000642084>] usb_hcd_irq
[173.604673] Disabling IRQ #228

Signed-off-by: William wu <wulf@rock-chips.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Mar 18, 2018
commit 1514839b366417934e2f1328edb50ed1e8a719f5 upstream.

This patch fixes NULL pointer crash due to active timer running for abort
IOCB.

From crash dump analysis it was discoverd that get_next_timer_interrupt()
encountered a corrupted entry on the timer list.

 OnePlusOSS#9 [ffff95e1f6f0fd40] page_fault at ffffffff914fe8f8
    [exception RIP: get_next_timer_interrupt+440]
    RIP: ffffffff90ea3088  RSP: ffff95e1f6f0fdf0  RFLAGS: 00010013
    RAX: ffff95e1f6451028  RBX: 000218e2389e5f40  RCX: 00000001232ad600
    RDX: 0000000000000001  RSI: ffff95e1f6f0fdf0  RDI: 0000000001232ad6
    RBP: ffff95e1f6f0fe40   R8: ffff95e1f6451188   R9: 0000000000000001
    R10: 0000000000000016  R11: 0000000000000016  R12: 00000001232ad5f6
    R13: ffff95e1f6450000  R14: ffff95e1f6f0fdf8  R15: ffff95e1f6f0fe10
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018

Looking at the assembly of get_next_timer_interrupt(), address came
from %r8 (ffff95e1f6451188) which is pointing to list_head with single
entry at ffff95e5ff621178.

 0xffffffff90ea307a <get_next_timer_interrupt+426>:      mov    (%r8),%rdx
 0xffffffff90ea307d <get_next_timer_interrupt+429>:      cmp    %r8,%rdx
 0xffffffff90ea3080 <get_next_timer_interrupt+432>:      je     0xffffffff90ea30a7 <get_next_timer_interrupt+471>
 0xffffffff90ea3082 <get_next_timer_interrupt+434>:      nopw   0x0(%rax,%rax,1)
 0xffffffff90ea3088 <get_next_timer_interrupt+440>:      testb  $0x1,0x18(%rdx)

 crash> rd ffff95e1f6451188 10
 ffff95e1f6451188:  ffff95e5ff621178 ffff95e5ff621178   x.b.....x.b.....
 ffff95e1f6451198:  ffff95e1f6451198 ffff95e1f6451198   ..E.......E.....
 ffff95e1f64511a8:  ffff95e1f64511a8 ffff95e1f64511a8   ..E.......E.....
 ffff95e1f64511b8:  ffff95e77cf509a0 ffff95e77cf509a0   ...|.......|....
 ffff95e1f64511c8:  ffff95e1f64511c8 ffff95e1f64511c8   ..E.......E.....

 crash> rd ffff95e5ff621178 10
 ffff95e5ff621178:  0000000000000001 ffff95e15936aa00   ..........6Y....
 ffff95e5ff621188:  0000000000000000 00000000ffffffff   ................
 ffff95e5ff621198:  00000000000000a0 0000000000000010   ................
 ffff95e5ff6211a8:  ffff95e5ff621198 000000000000000c   ..b.............
 ffff95e5ff6211b8:  00000f5800000000 ffff95e751f8d720   ....X... ..Q....

 ffff95e5ff621178 belongs to freed mempool object at ffff95e5ff621080.

 CACHE            NAME                 OBJSIZE  ALLOCATED     TOTAL  SLABS  SSIZE
 ffff95dc7fd74d00 mnt_cache                384      19785     24948    594    16k
   SLAB              MEMORY            NODE  TOTAL  ALLOCATED  FREE
   ffffdc5dabfd8800  ffff95e5ff620000     1     42         29    13
   FREE / [ALLOCATED]
    ffff95e5ff621080  (cpu 6 cache)

Examining the contents of that memory reveals a pointer to a constant string
in the driver, "abort\0", which is set by qla24xx_async_abort_cmd().

 crash> rd ffffffffc059277c 20
 ffffffffc059277c:  6e490074726f6261 0074707572726574   abort.Interrupt.
 ffffffffc059278c:  00676e696c6c6f50 6920726576697244   Polling.Driver i
 ffffffffc059279c:  646f6d207325206e 6974736554000a65   n %s mode..Testi
 ffffffffc05927ac:  636976656420676e 786c252074612065   ng device at %lx
 ffffffffc05927bc:  6b63656843000a2e 646f727020676e69   ...Checking prod
 ffffffffc05927cc:  6f20444920746375 0a2e706968632066   uct ID of chip..
 ffffffffc05927dc:  5120646e756f4600 204130303232414c   .Found QLA2200A
 ffffffffc05927ec:  43000a2e70696843 20676e696b636568   Chip...Checking
 ffffffffc05927fc:  65786f626c69616d 6c636e69000a2e73   mailboxes...incl
 ffffffffc059280c:  756e696c2f656475 616d2d616d642f78   ude/linux/dma-ma

 crash> struct -ox srb_iocb
 struct srb_iocb {
           union {
               struct {...} logio;
               struct {...} els_logo;
               struct {...} tmf;
               struct {...} fxiocb;
               struct {...} abt;
               struct ct_arg ctarg;
               struct {...} mbx;
               struct {...} nack;
    [0x0 ] } u;
    [0xb8] struct timer_list timer;
    [0x108] void (*timeout)(void *);
 }
 SIZE: 0x110

 crash> ! bc
 ibase=16
 obase=10
 B8+40
 F8

The object is a srb_t, and at offset 0xf8 within that structure
(i.e. ffff95e5ff621080 + f8 -> ffff95e5ff621178) is a struct timer_list.

Cc: <stable@vger.kernel.org> OnePlusOSS#4.4+
Fixes: 4440e46 ("[SCSI] qla2xxx: Add IOCB Abort command asynchronous handling.")
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Apr 10, 2018
[ Upstream commit d754941225a7dbc61f6dd2173fa9498049f9a7ee ]

If, for any reason, userland shuts down iscsi transport interfaces
before proper logouts - like when logging in to LUNs manually, without
logging out on server shutdown, or when automated scripts can't
umount/logout from logged LUNs - kernel will hang forever on its
sd_sync_cache() logic, after issuing the SYNCHRONIZE_CACHE cmd to all
still existent paths.

PID: 1 TASK: ffff8801a69b8000 CPU: 1 COMMAND: "systemd-shutdow"
 #0 [ffff8801a69c3a30] __schedule at ffffffff8183e9ee
 #1 [ffff8801a69c3a80] schedule at ffffffff8183f0d5
 #2 [ffff8801a69c3a98] schedule_timeout at ffffffff81842199
 OnePlusOSS#3 [ffff8801a69c3b40] io_schedule_timeout at ffffffff8183e604
 OnePlusOSS#4 [ffff8801a69c3b70] wait_for_completion_io_timeout at ffffffff8183fc6c
 OnePlusOSS#5 [ffff8801a69c3bd0] blk_execute_rq at ffffffff813cfe10
 OnePlusOSS#6 [ffff8801a69c3c88] scsi_execute at ffffffff815c3fc7
 OnePlusOSS#7 [ffff8801a69c3cc8] scsi_execute_req_flags at ffffffff815c60fe
 OnePlusOSS#8 [ffff8801a69c3d30] sd_sync_cache at ffffffff815d37d7
 OnePlusOSS#9 [ffff8801a69c3da8] sd_shutdown at ffffffff815d3c3c

This happens because iscsi_eh_cmd_timed_out(), the transport layer
timeout helper, would tell the queue timeout function (scsi_times_out)
to reset the request timer over and over, until the session state is
back to logged in state. Unfortunately, during server shutdown, this
might never happen again.

Other option would be "not to handle" the issue in the transport
layer. That would trigger the error handler logic, which would also need
the session state to be logged in again.

Best option, for such case, is to tell upper layers that the command was
handled during the transport layer error handler helper, marking it as
DID_NO_CONNECT, which will allow completion and inform about the
problem.

After the session was marked as ISCSI_STATE_FAILED, due to the first
timeout during the server shutdown phase, all subsequent cmds will fail
to be queued, allowing upper logic to fail faster.

Signed-off-by: Rafael David Tinoco <rafael.tinoco@canonical.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Apr 13, 2018
[ Upstream commit d754941225a7dbc61f6dd2173fa9498049f9a7ee ]

If, for any reason, userland shuts down iscsi transport interfaces
before proper logouts - like when logging in to LUNs manually, without
logging out on server shutdown, or when automated scripts can't
umount/logout from logged LUNs - kernel will hang forever on its
sd_sync_cache() logic, after issuing the SYNCHRONIZE_CACHE cmd to all
still existent paths.

PID: 1 TASK: ffff8801a69b8000 CPU: 1 COMMAND: "systemd-shutdow"
 #0 [ffff8801a69c3a30] __schedule at ffffffff8183e9ee
 #1 [ffff8801a69c3a80] schedule at ffffffff8183f0d5
 #2 [ffff8801a69c3a98] schedule_timeout at ffffffff81842199
 OnePlusOSS#3 [ffff8801a69c3b40] io_schedule_timeout at ffffffff8183e604
 OnePlusOSS#4 [ffff8801a69c3b70] wait_for_completion_io_timeout at ffffffff8183fc6c
 OnePlusOSS#5 [ffff8801a69c3bd0] blk_execute_rq at ffffffff813cfe10
 OnePlusOSS#6 [ffff8801a69c3c88] scsi_execute at ffffffff815c3fc7
 OnePlusOSS#7 [ffff8801a69c3cc8] scsi_execute_req_flags at ffffffff815c60fe
 OnePlusOSS#8 [ffff8801a69c3d30] sd_sync_cache at ffffffff815d37d7
 OnePlusOSS#9 [ffff8801a69c3da8] sd_shutdown at ffffffff815d3c3c

This happens because iscsi_eh_cmd_timed_out(), the transport layer
timeout helper, would tell the queue timeout function (scsi_times_out)
to reset the request timer over and over, until the session state is
back to logged in state. Unfortunately, during server shutdown, this
might never happen again.

Other option would be "not to handle" the issue in the transport
layer. That would trigger the error handler logic, which would also need
the session state to be logged in again.

Best option, for such case, is to tell upper layers that the command was
handled during the transport layer error handler helper, marking it as
DID_NO_CONNECT, which will allow completion and inform about the
problem.

After the session was marked as ISCSI_STATE_FAILED, due to the first
timeout during the server shutdown phase, all subsequent cmds will fail
to be queued, allowing upper logic to fail faster.

Signed-off-by: Rafael David Tinoco <rafael.tinoco@canonical.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request May 30, 2018
[ Upstream commit 2bbea6e117357d17842114c65e9a9cf2d13ae8a3 ]

when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 OnePlusOSS#3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 OnePlusOSS#4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 OnePlusOSS#5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 OnePlusOSS#6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 OnePlusOSS#7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 OnePlusOSS#8 [ffff880078447da8] mount_bdev at ffffffff81202570
 OnePlusOSS#9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
OnePlusOSS#10 [ffff880078447e28] mount_fs at ffffffff81202d09
OnePlusOSS#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
OnePlusOSS#12 [ffff880078447ea8] do_mount at ffffffff81220fee
OnePlusOSS#13 [ffff880078447f28] sys_mount at ffffffff812218d6
OnePlusOSS#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block->s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 OnePlusOSS#3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 OnePlusOSS#4 [ffff8800784179d0] down_read at ffffffff8168cde0
 OnePlusOSS#5 [ffff8800784179e8] get_super at ffffffff81201cc7
 OnePlusOSS#6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 OnePlusOSS#7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 OnePlusOSS#8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 OnePlusOSS#9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
OnePlusOSS#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
OnePlusOSS#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
OnePlusOSS#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
OnePlusOSS#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
OnePlusOSS#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
OnePlusOSS#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
OnePlusOSS#16 [ffff880078417d00] do_last at ffffffff8120d53d
OnePlusOSS#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
OnePlusOSS#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
OnePlusOSS#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
OnePlusOSS#20 [ffff880078417f70] sys_open at ffffffff811fde4e
OnePlusOSS#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block->s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Jul 3, 2018
[ Upstream commit 9954b80b8c0e8abc98e17bba0fccd9876211ceaa ]

platform_domain_notifier contains a variable sized array, which the
pm_clk_notify() notifier treats as a NULL terminated array:

     for (con_id = clknb->con_ids; *con_id; con_id++)
             pm_clk_add(dev, *con_id);

Omitting the initialiser for con_ids means that the array is zero
sized, and there is no NULL terminator.  This leads to pm_clk_notify()
overrunning into what ever structure follows, which may not be NULL.
This leads to an oops:

Unable to handle kernel NULL pointer dereference at virtual address 0000008c
pgd = c0003000
[0000008c] *pgd=80000800004003c, *pmd=00000000c
Internal error: Oops: 206 [#1] PREEMPT SMP ARM
Modules linked in:c
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0+ OnePlusOSS#9
Hardware name: Keystone
PC is at strlen+0x0/0x34
LR is at kstrdup+0x18/0x54
pc : [<c0623340>]    lr : [<c0111d6c>]    psr: 20000013
sp : eec73dc0  ip : eed780c0  fp : 00000001
r10: 00000000  r9 : 00000000  r8 : eed71e10
r7 : 0000008c  r6 : 0000008c  r5 : 014000c0  r4 : c03a6ff4
r3 : c09445d0  r2 : 00000000  r1 : 014000c0  r0 : 0000008c
Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 30c5387d  Table: 00003000  DAC: fffffffd
Process swapper/0 (pid: 1, stack limit = 0xeec72210)
Stack: (0xeec73dc0 to 0xeec74000)
...
[<c0623340>] (strlen) from [<c0111d6c>] (kstrdup+0x18/0x54)
[<c0111d6c>] (kstrdup) from [<c03a6ff4>] (__pm_clk_add+0x58/0x120)
[<c03a6ff4>] (__pm_clk_add) from [<c03a731c>] (pm_clk_notify+0x64/0xa8)
[<c03a731c>] (pm_clk_notify) from [<c004614c>] (notifier_call_chain+0x44/0x84)
[<c004614c>] (notifier_call_chain) from [<c0046320>] (__blocking_notifier_call_chain+0x48/0x60)
[<c0046320>] (__blocking_notifier_call_chain) from [<c0046350>] (blocking_notifier_call_chain+0x18/0x20)
[<c0046350>] (blocking_notifier_call_chain) from [<c0390234>] (device_add+0x36c/0x534)
[<c0390234>] (device_add) from [<c047fc00>] (of_platform_device_create_pdata+0x70/0xa4)
[<c047fc00>] (of_platform_device_create_pdata) from [<c047fea0>] (of_platform_bus_create+0xf0/0x1ec)
[<c047fea0>] (of_platform_bus_create) from [<c047fff8>] (of_platform_populate+0x5c/0xac)
[<c047fff8>] (of_platform_populate) from [<c08b1f04>] (of_platform_default_populate_init+0x8c/0xa8)
[<c08b1f04>] (of_platform_default_populate_init) from [<c000a78c>] (do_one_initcall+0x3c/0x164)
[<c000a78c>] (do_one_initcall) from [<c087bd9c>] (kernel_init_freeable+0x10c/0x1d0)
[<c087bd9c>] (kernel_init_freeable) from [<c0628db0>] (kernel_init+0x8/0xf0)
[<c0628db0>] (kernel_init) from [<c00090d8>] (ret_from_fork+0x14/0x3c)
Exception stack(0xeec73fb0 to 0xeec73ff8)
3fa0:                                     00000000 00000000 00000000 00000000
3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
3fe0: 00000000 00000000 00000000 00000000 00000013 00000000
Code: e3520000 1afffff7 e12fff1e c0801730 (e5d02000)
---[ end trace cafa8f148e262e80 ]---

Fix this by adding the necessary initialiser.

Fixes: fc20ffe ("ARM: keystone: add PM domain support for clock management")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Aug 9, 2018
commit 89da619bc18d79bca5304724c11d4ba3b67ce2c6 upstream.

Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 OnePlusOSS#3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 OnePlusOSS#4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 OnePlusOSS#5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 OnePlusOSS#6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 OnePlusOSS#7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 OnePlusOSS#8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 OnePlusOSS#9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e225042 ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: stable@vger.kernel.org
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Huang Chong <huang.chong@zte.com.cn>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Sep 5, 2018
[ Upstream commit 934140ab028713a61de8bca58c05332416d037d1 ]

cachefiles_read_waiter() has the right to access a 'monitor' object by
virtue of being called under the waitqueue lock for one of the pages in its
purview.  However, it has no ref on that monitor object or on the
associated operation.

What it is allowed to do is to move the monitor object to the operation's
to_do list, but once it drops the work_lock, it's actually no longer
permitted to access that object.  However, it is trying to enqueue the
retrieval operation for processing - but it can only do this via a pointer
in the monitor object, something it shouldn't be doing.

If it doesn't enqueue the operation, the operation may not get processed.
If the order is flipped so that the enqueue is first, then it's possible
for the work processor to look at the to_do list before the monitor is
enqueued upon it.

Fix this by getting a ref on the operation so that we can trust that it
will still be there once we've added the monitor to the to_do list and
dropped the work_lock.  The op can then be enqueued after the lock is
dropped.

The bug can manifest in one of a couple of ways.  The first manifestation
looks like:

 FS-Cache:
 FS-Cache: Assertion failed
 FS-Cache: 6 == 5 is false
 ------------[ cut here ]------------
 kernel BUG at fs/fscache/operation.c:494!
 RIP: 0010:fscache_put_operation+0x1e3/0x1f0
 ...
 fscache_op_work_func+0x26/0x50
 process_one_work+0x131/0x290
 worker_thread+0x45/0x360
 kthread+0xf8/0x130
 ? create_worker+0x190/0x190
 ? kthread_cancel_work_sync+0x10/0x10
 ret_from_fork+0x1f/0x30

This is due to the operation being in the DEAD state (6) rather than
INITIALISED, COMPLETE or CANCELLED (5) because it's already passed through
fscache_put_operation().

The bug can also manifest like the following:

 kernel BUG at fs/fscache/operation.c:69!
 ...
    [exception RIP: fscache_enqueue_operation+246]
 ...
 OnePlusOSS#7 [ffff883fff083c10] fscache_enqueue_operation at ffffffffa0b793c6
 OnePlusOSS#8 [ffff883fff083c28] cachefiles_read_waiter at ffffffffa0b15a48
 OnePlusOSS#9 [ffff883fff083c48] __wake_up_common at ffffffff810af028

I'm not entirely certain as to which is line 69 in Lei's kernel, so I'm not
entirely clear which assertion failed.

Fixes: 9ae326a ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: Lei Xue <carmark.dlut@gmail.com>
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Reported-by: Anthony DeRobertis <aderobertis@metrics.net>
Reported-by: NeilBrown <neilb@suse.com>
Reported-by: Daniel Axtens <dja@axtens.net>
Reported-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Slim80 pushed a commit to Slim80/android_kernel_oneplus_msm8996 that referenced this pull request Sep 11, 2018
[ Upstream commit 934140ab028713a61de8bca58c05332416d037d1 ]

cachefiles_read_waiter() has the right to access a 'monitor' object by
virtue of being called under the waitqueue lock for one of the pages in its
purview.  However, it has no ref on that monitor object or on the
associated operation.

What it is allowed to do is to move the monitor object to the operation's
to_do list, but once it drops the work_lock, it's actually no longer
permitted to access that object.  However, it is trying to enqueue the
retrieval operation for processing - but it can only do this via a pointer
in the monitor object, something it shouldn't be doing.

If it doesn't enqueue the operation, the operation may not get processed.
If the order is flipped so that the enqueue is first, then it's possible
for the work processor to look at the to_do list before the monitor is
enqueued upon it.

Fix this by getting a ref on the operation so that we can trust that it
will still be there once we've added the monitor to the to_do list and
dropped the work_lock.  The op can then be enqueued after the lock is
dropped.

The bug can manifest in one of a couple of ways.  The first manifestation
looks like:

 FS-Cache:
 FS-Cache: Assertion failed
 FS-Cache: 6 == 5 is false
 ------------[ cut here ]------------
 kernel BUG at fs/fscache/operation.c:494!
 RIP: 0010:fscache_put_operation+0x1e3/0x1f0
 ...
 fscache_op_work_func+0x26/0x50
 process_one_work+0x131/0x290
 worker_thread+0x45/0x360
 kthread+0xf8/0x130
 ? create_worker+0x190/0x190
 ? kthread_cancel_work_sync+0x10/0x10
 ret_from_fork+0x1f/0x30

This is due to the operation being in the DEAD state (6) rather than
INITIALISED, COMPLETE or CANCELLED (5) because it's already passed through
fscache_put_operation().

The bug can also manifest like the following:

 kernel BUG at fs/fscache/operation.c:69!
 ...
    [exception RIP: fscache_enqueue_operation+246]
 ...
 OnePlusOSS#7 [ffff883fff083c10] fscache_enqueue_operation at ffffffffa0b793c6
 OnePlusOSS#8 [ffff883fff083c28] cachefiles_read_waiter at ffffffffa0b15a48
 OnePlusOSS#9 [ffff883fff083c48] __wake_up_common at ffffffff810af028

I'm not entirely certain as to which is line 69 in Lei's kernel, so I'm not
entirely clear which assertion failed.

Fixes: 9ae326a ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: Lei Xue <carmark.dlut@gmail.com>
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Reported-by: Anthony DeRobertis <aderobertis@metrics.net>
Reported-by: NeilBrown <neilb@suse.com>
Reported-by: Daniel Axtens <dja@axtens.net>
Reported-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Dec 17, 2018
[ Upstream commit c5a94f434c82529afda290df3235e4d85873c5b4 ]

It was observed that a process blocked indefintely in
__fscache_read_or_alloc_page(), waiting for FSCACHE_COOKIE_LOOKING_UP
to be cleared via fscache_wait_for_deferred_lookup().

At this time, ->backing_objects was empty, which would normaly prevent
__fscache_read_or_alloc_page() from getting to the point of waiting.
This implies that ->backing_objects was cleared *after*
__fscache_read_or_alloc_page was was entered.

When an object is "killed" and then "dropped",
FSCACHE_COOKIE_LOOKING_UP is cleared in fscache_lookup_failure(), then
KILL_OBJECT and DROP_OBJECT are "called" and only in DROP_OBJECT is
->backing_objects cleared.  This leaves a window where
something else can set FSCACHE_COOKIE_LOOKING_UP and
__fscache_read_or_alloc_page() can start waiting, before
->backing_objects is cleared

There is some uncertainty in this analysis, but it seems to be fit the
observations.  Adding the wake in this patch will be handled correctly
by __fscache_read_or_alloc_page(), as it checks if ->backing_objects
is empty again, after waiting.

Customer which reported the hang, also report that the hang cannot be
reproduced with this fix.

The backtrace for the blocked process looked like:

PID: 29360  TASK: ffff881ff2ac0f80  CPU: 3   COMMAND: "zsh"
 #0 [ffff881ff43efbf8] schedule at ffffffff815e56f1
 #1 [ffff881ff43efc58] bit_wait at ffffffff815e64ed
 #2 [ffff881ff43efc68] __wait_on_bit at ffffffff815e61b8
 OnePlusOSS#3 [ffff881ff43efca0] out_of_line_wait_on_bit at ffffffff815e625e
 OnePlusOSS#4 [ffff881ff43efd08] fscache_wait_for_deferred_lookup at ffffffffa04f2e8f [fscache]
 OnePlusOSS#5 [ffff881ff43efd18] __fscache_read_or_alloc_page at ffffffffa04f2ffe [fscache]
 OnePlusOSS#6 [ffff881ff43efd58] __nfs_readpage_from_fscache at ffffffffa0679668 [nfs]
 OnePlusOSS#7 [ffff881ff43efd78] nfs_readpage at ffffffffa067092b [nfs]
 OnePlusOSS#8 [ffff881ff43efda0] generic_file_read_iter at ffffffff81187a73
 OnePlusOSS#9 [ffff881ff43efe50] nfs_file_read at ffffffffa066544b [nfs]
OnePlusOSS#10 [ffff881ff43efe70] __vfs_read at ffffffff811fc756
OnePlusOSS#11 [ffff881ff43efee8] vfs_read at ffffffff811fccfa
OnePlusOSS#12 [ffff881ff43eff18] sys_read at ffffffff811fda62
OnePlusOSS#13 [ffff881ff43eff50] entry_SYSCALL_64_fastpath at ffffffff815e986e

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Slim80 pushed a commit to Slim80/android_kernel_oneplus_msm8996 that referenced this pull request Dec 26, 2018
[ Upstream commit c5a94f434c82529afda290df3235e4d85873c5b4 ]

It was observed that a process blocked indefintely in
__fscache_read_or_alloc_page(), waiting for FSCACHE_COOKIE_LOOKING_UP
to be cleared via fscache_wait_for_deferred_lookup().

At this time, ->backing_objects was empty, which would normaly prevent
__fscache_read_or_alloc_page() from getting to the point of waiting.
This implies that ->backing_objects was cleared *after*
__fscache_read_or_alloc_page was was entered.

When an object is "killed" and then "dropped",
FSCACHE_COOKIE_LOOKING_UP is cleared in fscache_lookup_failure(), then
KILL_OBJECT and DROP_OBJECT are "called" and only in DROP_OBJECT is
->backing_objects cleared.  This leaves a window where
something else can set FSCACHE_COOKIE_LOOKING_UP and
__fscache_read_or_alloc_page() can start waiting, before
->backing_objects is cleared

There is some uncertainty in this analysis, but it seems to be fit the
observations.  Adding the wake in this patch will be handled correctly
by __fscache_read_or_alloc_page(), as it checks if ->backing_objects
is empty again, after waiting.

Customer which reported the hang, also report that the hang cannot be
reproduced with this fix.

The backtrace for the blocked process looked like:

PID: 29360  TASK: ffff881ff2ac0f80  CPU: 3   COMMAND: "zsh"
 #0 [ffff881ff43efbf8] schedule at ffffffff815e56f1
 OnePlusOSS#1 [ffff881ff43efc58] bit_wait at ffffffff815e64ed
 OnePlusOSS#2 [ffff881ff43efc68] __wait_on_bit at ffffffff815e61b8
 OnePlusOSS#3 [ffff881ff43efca0] out_of_line_wait_on_bit at ffffffff815e625e
 OnePlusOSS#4 [ffff881ff43efd08] fscache_wait_for_deferred_lookup at ffffffffa04f2e8f [fscache]
 OnePlusOSS#5 [ffff881ff43efd18] __fscache_read_or_alloc_page at ffffffffa04f2ffe [fscache]
 OnePlusOSS#6 [ffff881ff43efd58] __nfs_readpage_from_fscache at ffffffffa0679668 [nfs]
 OnePlusOSS#7 [ffff881ff43efd78] nfs_readpage at ffffffffa067092b [nfs]
 OnePlusOSS#8 [ffff881ff43efda0] generic_file_read_iter at ffffffff81187a73
 OnePlusOSS#9 [ffff881ff43efe50] nfs_file_read at ffffffffa066544b [nfs]
OnePlusOSS#10 [ffff881ff43efe70] __vfs_read at ffffffff811fc756
OnePlusOSS#11 [ffff881ff43efee8] vfs_read at ffffffff811fccfa
OnePlusOSS#12 [ffff881ff43eff18] sys_read at ffffffff811fda62
OnePlusOSS#13 [ffff881ff43eff50] entry_SYSCALL_64_fastpath at ffffffff815e986e

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ppajda pushed a commit to ppajda/android_kernel_oneplus_msm8996 that referenced this pull request Mar 21, 2019
As Jiqun Li reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=202883

sometimes, dead lock when make system call SYS_getdents64 with fsync() is
called by another process.

monkey running on android9.0

1.  task 9785 held sbi->cp_rwsem and waiting lock_page()
2.  task 10349 held mm_sem and waiting sbi->cp_rwsem
3. task 9709 held lock_page() and waiting mm_sem

so this is a dead lock scenario.

task stack is show by crash tools as following

crash_arm64> bt ffffffc03c354080
PID: 9785   TASK: ffffffc03c354080  CPU: 1   COMMAND: "RxIoScheduler-3"
>> OnePlusOSS#7 [ffffffc01b50fac0] __lock_page at ffffff80081b11e8

crash-arm64> bt 10349
PID: 10349  TASK: ffffffc018b83080  CPU: 1   COMMAND: "BUGLY_ASYNC_UPL"
>> OnePlusOSS#3 [ffffffc01f8cfa40] rwsem_down_read_failed at ffffff8008a93afc
     PC: 00000033  LR: 00000000  SP: 00000000  PSTATE: ffffffffffffffff

crash-arm64> bt 9709
PID: 9709   TASK: ffffffc03e7f3080  CPU: 1   COMMAND: "IntentService[A"
>> OnePlusOSS#3 [ffffffc001e67850] rwsem_down_read_failed at ffffff8008a93afc
>> OnePlusOSS#8 [ffffffc001e67b80] el1_ia at ffffff8008084fc4
     PC: ffffff8008274114  [compat_filldir64+120]
     LR: ffffff80083584d4  [f2fs_fill_dentries+448]
     SP: ffffffc001e67b80  PSTATE: 80400145
    X29: ffffffc001e67b80  X28: 0000000000000000  X27: 000000000000001a
    X26: 00000000000093d7  X25: ffffffc070d52480  X24: 0000000000000008
    X23: 0000000000000028  X22: 00000000d43dfd60  X21: ffffffc001e67e90
    X20: 0000000000000011  X19: ffffff80093a4000  X18: 0000000000000000
    X17: 0000000000000000  X16: 0000000000000000  X15: 0000000000000000
    X14: ffffffffffffffff  X13: 0000000000000008  X12: 0101010101010101
    X11: 7f7f7f7f7f7f7f7f  X10: 6a6a6a6a6a6a6a6a   X9: 7f7f7f7f7f7f7f7f
     X8: 0000000080808000   X7: ffffff800827409c   X6: 0000000080808000
     X5: 0000000000000008   X4: 00000000000093d7   X3: 000000000000001a
     X2: 0000000000000011   X1: ffffffc070d52480   X0: 0000000000800238
>> OnePlusOSS#9 [ffffffc001e67be0] f2fs_fill_dentries at ffffff80083584d0
     PC: 0000003c  LR: 00000000  SP: 00000000  PSTATE: 000000d9
    X12: f48a02ff X11: d4678960 X10: d43dfc00  X9: d4678ae4
     X8: 00000058  X7: d4678994  X6: d43de800  X5: 000000d9
     X4: d43dfc0c  X3: d43dfc10  X2: d46799c8  X1: 00000000
     X0: 00001068

Below potential deadlock will happen between three threads:
Thread A		Thread B		Thread C
- f2fs_do_sync_file
 - f2fs_write_checkpoint
  - down_write(&sbi->node_change) -- 1)
			- do_page_fault
			 - down_write(&mm->mmap_sem) -- 2)
			  - do_wp_page
			   - f2fs_vm_page_mkwrite
						- getdents64
						 - f2fs_read_inline_dir
						  - lock_page -- 3)
  - f2fs_sync_node_pages
   - lock_page -- 3)
			    - __do_map_lock
			     - down_read(&sbi->node_change) -- 1)
						  - f2fs_fill_dentries
						   - dir_emit
						    - compat_filldir64
						     - do_page_fault
						      - down_read(&mm->mmap_sem) -- 2)

Since f2fs_readdir is protected by inode.i_rwsem, there should not be
any updates in inode page, we're safe to lookup dents in inode page
without its lock held, so taking off the lock to improve concurrency
of readdir and avoid potential deadlock.

Reported-by: Jiqun Li <jiqun.li@unisoc.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
nathanchance pushed a commit to android-linux-stable/op3 that referenced this pull request Apr 27, 2019
[ Upstream commit d982b33133284fa7efa0e52ae06b88f9be3ea764 ]

  =================================================================
  ==20875==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 1160 byte(s) in 1 object(s) allocated from:
      #0 0x7f1b6fc84138 in calloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xee138)
      #1 0x55bd50005599 in zalloc util/util.h:23
      #2 0x55bd500068f5 in perf_evsel__newtp_idx util/evsel.c:327
      OnePlusOSS#3 0x55bd4ff810fc in perf_evsel__newtp /home/work/linux/tools/perf/util/evsel.h:216
      OnePlusOSS#4 0x55bd4ff81608 in test__perf_evsel__tp_sched_test tests/evsel-tp-sched.c:69
      OnePlusOSS#5 0x55bd4ff528e6 in run_test tests/builtin-test.c:358
      OnePlusOSS#6 0x55bd4ff52baf in test_and_print tests/builtin-test.c:388
      OnePlusOSS#7 0x55bd4ff543fe in __cmd_test tests/builtin-test.c:583
      OnePlusOSS#8 0x55bd4ff5572f in cmd_test tests/builtin-test.c:722
      OnePlusOSS#9 0x55bd4ffc4087 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302
      OnePlusOSS#10 0x55bd4ffc45c6 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354
      OnePlusOSS#11 0x55bd4ffc49ca in run_argv /home/changbin/work/linux/tools/perf/perf.c:398
      OnePlusOSS#12 0x55bd4ffc5138 in main /home/changbin/work/linux/tools/perf/perf.c:520
      OnePlusOSS#13 0x7f1b6e34809a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a)

  Indirect leak of 19 byte(s) in 1 object(s) allocated from:
      #0 0x7f1b6fc83f30 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xedf30)
      #1 0x7f1b6e3ac30f in vasprintf (/lib/x86_64-linux-gnu/libc.so.6+0x8830f)

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Fixes: 6a6cd11 ("perf test: Add test for the sched tracepoint format fields")
Link: http://lkml.kernel.org/r/20190316080556.3075-17-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ppajda pushed a commit to ppajda/android_kernel_oneplus_msm8996 that referenced this pull request May 29, 2019
As Jiqun Li reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=202883

sometimes, dead lock when make system call SYS_getdents64 with fsync() is
called by another process.

monkey running on android9.0

1.  task 9785 held sbi->cp_rwsem and waiting lock_page()
2.  task 10349 held mm_sem and waiting sbi->cp_rwsem
3. task 9709 held lock_page() and waiting mm_sem

so this is a dead lock scenario.

task stack is show by crash tools as following

crash_arm64> bt ffffffc03c354080
PID: 9785   TASK: ffffffc03c354080  CPU: 1   COMMAND: "RxIoScheduler-3"
>> OnePlusOSS#7 [ffffffc01b50fac0] __lock_page at ffffff80081b11e8

crash-arm64> bt 10349
PID: 10349  TASK: ffffffc018b83080  CPU: 1   COMMAND: "BUGLY_ASYNC_UPL"
>> OnePlusOSS#3 [ffffffc01f8cfa40] rwsem_down_read_failed at ffffff8008a93afc
     PC: 00000033  LR: 00000000  SP: 00000000  PSTATE: ffffffffffffffff

crash-arm64> bt 9709
PID: 9709   TASK: ffffffc03e7f3080  CPU: 1   COMMAND: "IntentService[A"
>> OnePlusOSS#3 [ffffffc001e67850] rwsem_down_read_failed at ffffff8008a93afc
>> OnePlusOSS#8 [ffffffc001e67b80] el1_ia at ffffff8008084fc4
     PC: ffffff8008274114  [compat_filldir64+120]
     LR: ffffff80083584d4  [f2fs_fill_dentries+448]
     SP: ffffffc001e67b80  PSTATE: 80400145
    X29: ffffffc001e67b80  X28: 0000000000000000  X27: 000000000000001a
    X26: 00000000000093d7  X25: ffffffc070d52480  X24: 0000000000000008
    X23: 0000000000000028  X22: 00000000d43dfd60  X21: ffffffc001e67e90
    X20: 0000000000000011  X19: ffffff80093a4000  X18: 0000000000000000
    X17: 0000000000000000  X16: 0000000000000000  X15: 0000000000000000
    X14: ffffffffffffffff  X13: 0000000000000008  X12: 0101010101010101
    X11: 7f7f7f7f7f7f7f7f  X10: 6a6a6a6a6a6a6a6a   X9: 7f7f7f7f7f7f7f7f
     X8: 0000000080808000   X7: ffffff800827409c   X6: 0000000080808000
     X5: 0000000000000008   X4: 00000000000093d7   X3: 000000000000001a
     X2: 0000000000000011   X1: ffffffc070d52480   X0: 0000000000800238
>> OnePlusOSS#9 [ffffffc001e67be0] f2fs_fill_dentries at ffffff80083584d0
     PC: 0000003c  LR: 00000000  SP: 00000000  PSTATE: 000000d9
    X12: f48a02ff X11: d4678960 X10: d43dfc00  X9: d4678ae4
     X8: 00000058  X7: d4678994  X6: d43de800  X5: 000000d9
     X4: d43dfc0c  X3: d43dfc10  X2: d46799c8  X1: 00000000
     X0: 00001068

Below potential deadlock will happen between three threads:
Thread A		Thread B		Thread C
- f2fs_do_sync_file
 - f2fs_write_checkpoint
  - down_write(&sbi->node_change) -- 1)
			- do_page_fault
			 - down_write(&mm->mmap_sem) -- 2)
			  - do_wp_page
			   - f2fs_vm_page_mkwrite
						- getdents64
						 - f2fs_read_inline_dir
						  - lock_page -- 3)
  - f2fs_sync_node_pages
   - lock_page -- 3)
			    - __do_map_lock
			     - down_read(&sbi->node_change) -- 1)
						  - f2fs_fill_dentries
						   - dir_emit
						    - compat_filldir64
						     - do_page_fault
						      - down_read(&mm->mmap_sem) -- 2)

Since f2fs_readdir is protected by inode.i_rwsem, there should not be
any updates in inode page, we're safe to lookup dents in inode page
without its lock held, so taking off the lock to improve concurrency
of readdir and avoid potential deadlock.

Reported-by: Jiqun Li <jiqun.li@unisoc.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
ppajda pushed a commit to ppajda/android_kernel_oneplus_msm8996 that referenced this pull request Sep 8, 2019
commit cf3591ef832915892f2499b7e54b51d4c578b28c upstream.

Revert the commit bd293d071ffe65e645b4d8104f9d8fe15ea13862. The proper
fix has been made available with commit d0a255e795ab ("loop: set
PF_MEMALLOC_NOIO for the worker thread").

Note that the fix offered by commit bd293d071ffe doesn't really prevent
the deadlock from occuring - if we look at the stacktrace reported by
Junxiao Bi, we see that it hangs in bit_wait_io and not on the mutex -
i.e. it has already successfully taken the mutex. Changing the mutex
from mutex_lock to mutex_trylock won't help with deadlocks that happen
afterwards.

PID: 474    TASK: ffff8813e11f4600  CPU: 10  COMMAND: "kswapd0"
   #0 [ffff8813dedfb938] __schedule at ffffffff8173f405
   OnePlusOSS#1 [ffff8813dedfb990] schedule at ffffffff8173fa27
   OnePlusOSS#2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
   OnePlusOSS#3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
   OnePlusOSS#4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
   OnePlusOSS#5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
   OnePlusOSS#6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
   OnePlusOSS#7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
   OnePlusOSS#8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
   OnePlusOSS#9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
  OnePlusOSS#10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
  OnePlusOSS#11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
  OnePlusOSS#12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
  OnePlusOSS#13 [ffff8813dedfbec0] kthread at ffffffff810a8428
  OnePlusOSS#14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Fixes: bd293d071ffe ("dm bufio: fix deadlock with loop device")
Depends-on: d0a255e795ab ("loop: set PF_MEMALLOC_NOIO for the worker thread")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I6cd6b254cca8cb8e72c197d44b91790c1a799554
ppajda pushed a commit to ppajda/android_kernel_oneplus_msm8996 that referenced this pull request Mar 3, 2020
[ Upstream commit 42ffb0bf584ae5b6b38f72259af1e0ee417ac77f ]

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   OnePlusOSS#1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   OnePlusOSS#2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   OnePlusOSS#3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   OnePlusOSS#4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   OnePlusOSS#5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   OnePlusOSS#6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   OnePlusOSS#7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   OnePlusOSS#8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   OnePlusOSS#9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   OnePlusOSS#1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   OnePlusOSS#2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   OnePlusOSS#3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   OnePlusOSS#4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   OnePlusOSS#5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   OnePlusOSS#6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   OnePlusOSS#7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   OnePlusOSS#8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   OnePlusOSS#9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: I5daee5ea01df5eb76df156cb489140e58826cab4
ppajda pushed a commit to ppajda/android_kernel_oneplus_msm8996 that referenced this pull request Mar 7, 2020
[ Upstream commit 42ffb0bf584ae5b6b38f72259af1e0ee417ac77f ]

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   OnePlusOSS#1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   OnePlusOSS#2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   OnePlusOSS#3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   OnePlusOSS#4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   OnePlusOSS#5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   OnePlusOSS#6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   OnePlusOSS#7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   OnePlusOSS#8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   OnePlusOSS#9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   OnePlusOSS#1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   OnePlusOSS#2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   OnePlusOSS#3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   OnePlusOSS#4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   OnePlusOSS#5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   OnePlusOSS#6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   OnePlusOSS#7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   OnePlusOSS#8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   OnePlusOSS#9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: I5daee5ea01df5eb76df156cb489140e58826cab4
ppajda pushed a commit to ppajda/android_kernel_oneplus_msm8996 that referenced this pull request Mar 22, 2020
[ Upstream commit 42ffb0bf584ae5b6b38f72259af1e0ee417ac77f ]

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   OnePlusOSS#1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   OnePlusOSS#2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   OnePlusOSS#3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   OnePlusOSS#4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   OnePlusOSS#5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   OnePlusOSS#6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   OnePlusOSS#7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   OnePlusOSS#8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   OnePlusOSS#9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   OnePlusOSS#1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   OnePlusOSS#2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   OnePlusOSS#3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   OnePlusOSS#4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   OnePlusOSS#5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   OnePlusOSS#6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   OnePlusOSS#7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   OnePlusOSS#8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   OnePlusOSS#9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: I5daee5ea01df5eb76df156cb489140e58826cab4
ppajda pushed a commit to ppajda/android_kernel_oneplus_msm8996 that referenced this pull request Jul 4, 2020
commit 420902c9d086848a7548c83e0a49021514bd71b7 upstream.

If we hold the superblock lock while calling reiserfs_quota_on_mount(), we can
deadlock our own worker - mount blocks kworker/3:2, sleeps forever more.

crash> ps|grep UN
    715      2   3  ffff880220734d30  UN   0.0       0      0  [kworker/3:2]
   9369   9341   2  ffff88021ffb7560  UN   1.3  493404 123184  Xorg
   9665   9664   3  ffff880225b92ab0  UN   0.0   47368    812  udisks-daemon
  10635  10403   3  ffff880222f22c70  UN   0.0   14904    936  mount
crash> bt ffff880220734d30
PID: 715    TASK: ffff880220734d30  CPU: 3   COMMAND: "kworker/3:2"
 #0 [ffff8802244c3c20] schedule at ffffffff8144584b
 OnePlusOSS#1 [ffff8802244c3cc8] __rt_mutex_slowlock at ffffffff814472b3
 OnePlusOSS#2 [ffff8802244c3d28] rt_mutex_slowlock at ffffffff814473f5
 OnePlusOSS#3 [ffff8802244c3dc8] reiserfs_write_lock at ffffffffa05f28fd [reiserfs]
 OnePlusOSS#4 [ffff8802244c3de8] flush_async_commits at ffffffffa05ec91d [reiserfs]
 OnePlusOSS#5 [ffff8802244c3e08] process_one_work at ffffffff81073726
 OnePlusOSS#6 [ffff8802244c3e68] worker_thread at ffffffff81073eba
 OnePlusOSS#7 [ffff8802244c3ec8] kthread at ffffffff810782e0
 OnePlusOSS#8 [ffff8802244c3f48] kernel_thread_helper at ffffffff81450064
crash> rd ffff8802244c3cc8 10
ffff8802244c3cc8:  ffffffff814472b3 ffff880222f23250   .rD.....P2."....
ffff8802244c3cd8:  0000000000000000 0000000000000286   ................
ffff8802244c3ce8:  ffff8802244c3d30 ffff880220734d80   0=L$.....Ms ....
ffff8802244c3cf8:  ffff880222e8f628 0000000000000000   (.."............
ffff8802244c3d08:  0000000000000000 0000000000000002   ................
crash> struct rt_mutex ffff880222e8f628
struct rt_mutex {
  wait_lock = {
    raw_lock = {
      slock = 65537
    }
  },
  wait_list = {
    node_list = {
      next = 0xffff8802244c3d48,
      prev = 0xffff8802244c3d48
    }
  },
  owner = 0xffff880222f22c71,
  save_state = 0
}
crash> bt 0xffff880222f22c70
PID: 10635  TASK: ffff880222f22c70  CPU: 3   COMMAND: "mount"
 #0 [ffff8802216a9868] schedule at ffffffff8144584b
 OnePlusOSS#1 [ffff8802216a9910] schedule_timeout at ffffffff81446865
 OnePlusOSS#2 [ffff8802216a99a0] wait_for_common at ffffffff81445f74
 OnePlusOSS#3 [ffff8802216a9a30] flush_work at ffffffff810712d3
 OnePlusOSS#4 [ffff8802216a9ab0] schedule_on_each_cpu at ffffffff81074463
 OnePlusOSS#5 [ffff8802216a9ae0] invalidate_bdev at ffffffff81178aba
 OnePlusOSS#6 [ffff8802216a9af0] vfs_load_quota_inode at ffffffff811a3632
 OnePlusOSS#7 [ffff8802216a9b50] dquot_quota_on_mount at ffffffff811a375c
 OnePlusOSS#8 [ffff8802216a9b80] finish_unfinished at ffffffffa05dd8b0 [reiserfs]
 OnePlusOSS#9 [ffff8802216a9cc0] reiserfs_fill_super at ffffffffa05de825 [reiserfs]
    RIP: 00007f7b9303997a  RSP: 00007ffff443c7a8  RFLAGS: 00010202
    RAX: 00000000000000a5  RBX: ffffffff8144ef12  RCX: 00007f7b932e9ee0
    RDX: 00007f7b93d9a400  RSI: 00007f7b93d9a3e0  RDI: 00007f7b93d9a3c0
    RBP: 00007f7b93d9a2c0   R8: 00007f7b93d9a550   R9: 0000000000000001
    R10: ffffffffc0ed040e  R11: 0000000000000202  R12: 000000000000040e
    R13: 0000000000000000  R14: 00000000c0ed040e  R15: 00007ffff443ca20
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: Ib963e18e5994a15e985b567c8b504ef91484e66d
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