Have you seen anything like this? It could be one of my patches that broke it: 00135 fio[39217]: segfault at 560494fe654c ip 00007fe9fb6b3e67 sp 00007ffc8f08b6d0 error 4 in libc.so.6[7fe9fb645000+155000] likely on CPU 0 (core 0, socket 0) 00135 Code: 1f 40 00 48 83 ec 08 48 8b 4f 08 48 89 c8 48 83 e0 f8 48 3b 04 07 0f 85 a9 00 00 00 f3 0f 6f 47 10 48 8b 57 18 66 48 0f 7e c0 <48> 3b 78 18 75 7b 48 3b 7a 10 75 75 48 8b 77 10 48 89 50 18 66 0f 00363 INFO: task fsstress:39216 blocked for more than 120 seconds. 00363 Not tainted 6.4.0-rc5-00028-gf824d48d50fc #391 00363 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 00363 task:fsstress state:D stack:11496 pid:39216 ppid:39214 flags:0x00000002 00363 Call Trace: [snip] 00363 wait_for_completion_state+0x11c/0x1e0 00363 do_coredump+0x265/0x15b0 00363 get_signal+0x904/0x9c0 00363 arch_do_signal_or_restart+0x1b/0x250 00363 exit_to_user_mode_prepare+0x99/0x100 00363 syscall_exit_to_user_mode+0x21/0x40 # cat /proc/39216/stack [<0>] do_coredump+0x265/0x15b0 [<0>] get_signal+0x904/0x9c0 [<0>] arch_do_signal_or_restart+0x1b/0x250 [<0>] exit_to_user_mode_prepare+0x99/0x100 [<0>] syscall_exit_to_user_mode+0x21/0x40 [<0>] do_syscall_64+0x40/0x80 [<0>] entry_SYSCALL_64_after_hwframe+0x63/0xcd # cat /proc/39214/stack [<0>] do_wait+0x161/0x2f0 [<0>] kernel_wait4+0x8a/0x110 [<0>] __do_sys_wait4+0x67/0x80 [<0>] __x64_sys_wait4+0x17/0x20 [<0>] do_syscall_64+0x34/0x80 [<0>] entry_SYSCALL_64_after_hwframe+0x63/0xcd Those are the only two pids running fsstress. # ps -aux | grep fsstress root 39214 0.0 0.0 2580 1664 ? S 15:11 0:00 ./ltp/fsstress -p 1 -n999999999 -f setattr 0 -ffsync 0 -fsync 0 -ffdatasync 0 -f setattr 1 -d /mnt/scratch/fsstress.39009 root 39216 0.3 0.3 8024 6792 ? D 15:11 0:02 ./ltp/fsstress -p 1 -n999999999 -f setattr 0 -ffsync 0 -fsync 0 -ffdatasync 0 -f setattr 1 -d /mnt/scratch/fsstress.39009 Obviously fio shouldn't've segfaulted in the first place, but sometimes when it does, fsstress hangs during coredump, and that also seems like it shouldn't happen.
