pixz deadlocks on some input files

[hochhaus]

I used xz 5.2.1 w/ -9 --threads=0 on a large input file. When I run pixz -d to decompress it, pixz appears to deadlock (and never terminates).

The backtrace for pixz is included below. I apologize that I cannot provide access to the problematic *.xz file as it contains confidential information. I have successfully been able to decompress other files using pixz which were compressed with "xz -9 --thread=0" so I believe that the issue is somehow data dependent to this particular file.

Other than supplying access to the problematic *.xz file can I do anything to help get the required information for debugging?

Thanks and sorry for the vague bug report.

(gdb) thread apply all bt

Thread 6 (Thread 0x7f47827f3700 (LWP 1290)):
#0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1 0x00000000004036db in ?? ()
#2 0x0000000000403c41 in ?? ()
#3 0x00000000004029da in ?? ()
#4 0x00007f47845680a4 in start_thread (arg=0x7f47827f3700) at pthread_create.c:309
#5 0x00007f4783ad204d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 5 (Thread 0x7f4781ff2700 (LWP 1291)):
#0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1 0x00000000004036db in ?? ()
#2 0x0000000000403c41 in ?? ()
#3 0x00000000004029da in ?? ()
#4 0x00007f47845680a4 in start_thread (arg=0x7f4781ff2700) at pthread_create.c:309
#5 0x00007f4783ad204d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7f47817f1700 (LWP 1292)):
#0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1 0x00000000004036db in ?? ()
#2 0x0000000000403c41 in ?? ()
#3 0x00000000004029da in ?? ()
#4 0x00007f47845680a4 in start_thread (arg=0x7f47817f1700) at pthread_create.c:309
#5 0x00007f4783ad204d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7f4780ff0700 (LWP 1293)):
#0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1 0x00000000004036db in ?? ()
#2 0x0000000000403c41 in ?? ()
#3 0x00000000004029da in ?? ()
#4 0x00007f47845680a4 in start_thread (arg=0x7f4780ff0700) at pthread_create.c:309
#5 0x00007f4783ad204d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f47807ef700 (LWP 1294)):
#0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1 0x00000000004036db in ?? ()
#2 0x0000000000404379 in ?? ()
#3 0x00000000004045b0 in ?? ()
#4 0x00000000004029ba in ?? ()
#5 0x00007f47845680a4 in start_thread (arg=0x7f47807ef700) at pthread_create.c:309
#6 0x00007f4783ad204d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f4784971700 (LWP 1289)):
#0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185

---Type to continue, or q to quit---
#1 0x00000000004036db in ?? ()
#2 0x0000000000403ad1 in ?? ()
#3 0x0000000000404b33 in ?? ()
#4 0x00000000004026aa in ?? ()
#5 0x00007f4783a0db45 in __libc_start_main (main=0x4023b0, argc=3, argv=0x7ffce811f178, init=, fini=, rtld_fini=, stack_end=0x7ffce811f168) at libc-start.c:287
#6 0x0000000000402805 in ?? ()