dsc_host keeps crashing

[arminfelder]

I keep getting, with my Oracle Linux 8 VM running in Azure :

[   24.670383] EXT4-fs (sda1): recovery complete
[   24.757619] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
[   24.959030] Adding 2097148k swap on /mnt/resource/swapfile.  Priority:-2 extents:6 across:2260988k FS
[   63.058142] hv_balloon: Max. dynamic memory size: 16384 MB
[  878.910461] dsc_host[4937]: segfault at 0 ip 0000000000000000 sp 00007ffde05b39b8 error 14 in dsc_host[400000+94000]
[  878.923608] Code: Bad RIP value.
[  879.921161] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060
[  879.929026] PGD 0 P4D 0 
[  879.929026] Oops: 0000 [#1] SMP PTI
[  879.937028] CPU: 0 PID: 4913 Comm: vsftpd Kdump: loaded Not tainted 4.18.0-240.10.1.el8_3.x86_64 #1
[  879.945030] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090008  12/07/2018
[  879.957029] RIP: 0010:d_path+0x34/0x140
[  879.961031] Code: 48 89 fb 48 83 ec 28 48 8b 7f 08 89 54 24 04 65 48 8b 04 25 28 00 00 00 48 89 44 24 20 31 c0 48 63 c2 48 01 f0 48 89 44 24 08 <48> 8b 47 60 48 85 c0 74 37 48 8b 40 48 48 85 c0 74 2e 48 3b 7f 18
[  879.981032] RSP: 0018:ffffc2be418d7e18 EFLAGS: 00010282
[  879.985020] RAX: ffff9f4c2d8e700b RBX: ffff9f4bf7189ab0 RCX: 0000000000000825
[  879.993027] RDX: 000000000000100b RSI: ffff9f4c2d8e6000 RDI: 0000000000000000
[  880.001040] RBP: ffffc2be418d7e48 R08: ffff9f4c2fa2f1c0 R09: ffff9f4887c02400
[  880.007115] R10: ffff9f4c206ec6c0 R11: ffff9f4c206ec031 R12: ffff9f4c2d8e6000
[  880.018063] R13: 0000000000000000 R14: ffff9f4bf7189800 R15: 0000000000000000
[  880.024013] FS:  00007f354b450740(0000) GS:ffff9f4c2fa00000(0000) knlGS:0000000000000000
[  880.030311] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  880.041203] CR2: 0000000000000060 CR3: 0000000477bbe006 CR4: 00000000003606f0
[  880.046032] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  880.046032] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  880.074048] Call Trace:
[  880.075023]  audit_log_d_path+0x6b/0xd0
[  880.075023]  audit_log_exit+0x66f/0xd40
[  880.075023]  ? audit_filter_inodes+0x2e/0x100
[  880.075023]  ? audit_filter_syscall.constprop.16+0x2c/0xd0
[  880.075023]  __audit_syscall_exit+0x238/0x2a0
[  880.075023]  syscall_slow_exit_work+0x101/0x130
[  880.075023]  do_syscall_64+0x170/0x1a0
[  880.110111]  entry_SYSCALL_64_after_hwframe+0x65/0xca
[  880.111025] RIP: 0033:0x7f354a1ce552
[  880.111025] Code: 25 00 00 41 00 3d 00 00 41 00 74 4c 48 8d 05 15 50 2d 00 8b 00 85 c0 75 6d 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 0f 87 a2 00 00 00 48 8b 4c 24 28 64 48 33 0c 25
[  880.126022] RSP: 002b:00007ffc55ad3180 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
[  880.126022] RAX: 0000000000000007 RBX: 00007ffc55ad3470 RCX: 00007f354a1ce552
[  880.152022] RDX: 0000000000000841 RSI: 0000556f5e4bbc20 RDI: 00000000ffffff9c
[  880.152022] RBP: 00007ffc55ad35c8 R08: 0000556f5e4ad014 R09: 0000000000000000
[  880.152022] R10: 00000000000001b6 R11: 0000000000000246 R12: 00007ffc55ad35f0
[  880.176046] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[  880.176046] Modules linked in: nft_counter xt_owner xt_conntrack ccm md4 sha512_ssse3 sha512_generic cmac nls_utf8 cifs libarc4 dns_resolver nf_nat_ftp nft_objref nf_conntrack_ftp nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_tables_set nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip6_tables nft_compat ip_set scsi_transport_iscsi nf_tables nfnetlink sunrpc intel_rapl_msr intel_rapl_common isst_if_mbox_msr isst_if_common nfit libnvdimm ext4 crct10dif_pclmul mbcache crc32_pclmul jbd2 ghash_clmulni_intel intel_rapl_perf pcspkr i2c_piix4 hv_balloon joydev ip_tables xfs libcrc32c ata_generic sd_mod sg hv_netvsc hyperv_keyboard hid_hyperv hv_utils hv_storvsc scsi_transport_fc hyperv_fb ata_piix libata crc32c_intel serio_raw hv_vmbus
[  880.747017] CR2: 0000000000000060
[  880.857127] ---[ end trace d370602d082db6cc ]---
[  880.941091] RIP: 0010:d_path+0x34/0x140
[  881.032023] Code: 48 89 fb 48 83 ec 28 48 8b 7f 08 89 54 24 04 65 48 8b 04 25 28 00 00 00 48 89 44 24 20 31 c0 48 63 c2 48 01 f0 48 89 44 24 08 <48> 8b 47 60 48 85 c0 74 37 48 8b 40 48 48 85 c0 74 2e 48 3b 7f 18
[  881.221603] RSP: 0018:ffffc2be418d7e18 EFLAGS: 00010282
[  881.304015] RAX: ffff9f4c2d8e700b RBX: ffff9f4bf7189ab0 RCX: 0000000000000825
[  881.401016] RDX: 000000000000100b RSI: ffff9f4c2d8e6000 RDI: 0000000000000000
[  881.503037] RBP: ffffc2be418d7e48 R08: ffff9f4c2fa2f1c0 R09: ffff9f4887c02400
[  881.596684] R10: ffff9f4c206ec6c0 R11: ffff9f4c206ec031 R12: ffff9f4c2d8e6000
[  881.681039] R13: 0000000000000000 R14: ffff9f4bf7189800 R15: 0000000000000000
[  881.765028] FS:  00007f354b450740(0000) GS:ffff9f4c2fa00000(0000) knlGS:0000000000000000
[  881.844807] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  881.933028] CR2: 0000000000000060 CR3: 0000000477bbe006 CR4: 00000000003606f0
[  882.033345] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  882.126024] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  882.214104] Kernel panic - not syncing: Fatal exception
[  882.301106] Kernel Offset: 0x27800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)

[sbonds]

You've got the same thing as Issue: #764

You also have an additional issue that causes the kernel panic since the dsc_host segfault should not be fatal to the OS.

Based on this it appears to be related to your auditing service:

[  880.074048] Call Trace:
[  880.075023]  audit_log_d_path+0x6b/0xd0
[  880.075023]  audit_log_exit+0x66f/0xd40
[  880.075023]  ? audit_filter_inodes+0x2e/0x100
[  880.075023]  ? audit_filter_syscall.constprop.16+0x2c/0xd0
[  880.075023]  __audit_syscall_exit+0x238/0x2a0
[  880.075023]  syscall_slow_exit_work+0x101/0x130
[  880.075023]  do_syscall_64+0x170/0x1a0
[  880.110111]  entry_SYSCALL_64_after_hwframe+0x65/0xca

See if you can use a recovery VM or init=/bin/bash from GRUB to get where you can run this to allow dsc_host to work:

sudo alternatives --set python /usr/bin/python3

Then you can set up kdump and collect a vmcore (kernel crash dump) to send to Oracle as part of your support agreement. You can undo the above "alternatives" to re-create the crash:

sudo alternatives --remove python /usr/bin/python3

[arminfelder]

@sbonds thanks , I found out, that the kernel panic was caused by a bug in the 4.18 kernel and not by dsc_host