syzbot


INFO: task hung in io_ring_exit_work

Status: auto-obsoleted due to no activity on 2023/10/10 09:34
Reported-by: syzbot+86f5509d20f473d56fd4@syzkaller.appspotmail.com
First crash: 598d, last: 508d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in io_ring_exit_work origin:lts-only syz done 11 494d 590d 0/3 auto-obsoleted due to no activity on 2024/10/10 00:14
upstream INFO: task hung in io_ring_exit_work io-uring C unreliable unreliable 820 506d 1326d 0/28 auto-obsoleted due to no activity on 2023/09/12 07:44

Sample crash report:
INFO: task kworker/u4:6:31444 blocked for more than 143 seconds.
      Not tainted 6.1.37-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:6    state:D stack:19680 pid:31444 ppid:2      flags:0x00004000
Workqueue: events_unbound io_ring_exit_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x132c/0x4330 kernel/sched/core.c:6554
 schedule+0xbf/0x180 kernel/sched/core.c:6630
 schedule_timeout+0xac/0x300 kernel/time/timer.c:1911
 do_wait_for_common+0x441/0x5e0 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x46/0x60 kernel/sched/completion.c:138
 io_ring_exit_work+0x6b4/0x794 io_uring/io_uring.c:2775
 process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
 worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
 kthread+0x26e/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cf27570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:510
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cf27d70 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:510
1 lock held by khungtaskd/28:
 #0: ffffffff8cf273a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3299:
 #0: ffff8880291ba098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2177
2 locks held by kworker/u4:13/4477:
 #0: ffff888012469138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
 #1: ffffc9000c2afd20 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
2 locks held by kworker/u4:6/31444:
 #0: ffff888012469138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
 #1: ffffc90006eafd20 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
2 locks held by kworker/u4:8/13976:
 #0: ffff888012469138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
 #1: ffffc9000b1f7d20 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.37-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1b0/0x3f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf18/0xf60 kernel/hung_task.c:377
 kthread+0x26e/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2982 Comm: syslogd Not tainted 6.1.37-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55
Code: 08 65 8b 1d 38 ec 7d 75 65 8b 05 e1 41 7e 75 a9 ff ff ff 7f 74 22 65 48 8b 04 25 28 00 00 00 48 3b 44 24 08 0f 85 c7 00 00 00 <89> d8 48 83 c4 10 5b 41 5c 41 5e 41 5f c3 48 c7 04 24 00 00 00 00
RSP: 0018:ffffc9000315f5f0 EFLAGS: 00000046
RAX: a17a09967bcc5d00 RBX: 0000000000000001 RCX: 0000000080000000
RDX: ffff88807e51d940 RSI: ffffffff8aebe3a0 RDI: ffffffff8b3ccda0
RBP: 0000000000000001 R08: ffffffff8a803427 R09: fffffbfff2051845
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000246
R13: ffff88807e51d940 R14: 00000000ffffffff R15: ffffffff8cf273a0
FS:  00007fd001088380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c002773000 CR3: 0000000028b74000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000003b DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
 lock_is_held_type+0xfd/0x180 kernel/locking/lockdep.c:5713
 xa_head include/linux/xarray.h:1182 [inline]
 xas_start+0x2d7/0x7b0 lib/xarray.c:188
 xas_load+0x28/0x140 lib/xarray.c:235
 mapping_get_entry mm/filemap.c:1853 [inline]
 __filemap_get_folio+0x205/0xe30 mm/filemap.c:1915
 shmem_get_folio_gfp+0x356/0x3470 mm/shmem.c:1862
 shmem_get_folio mm/shmem.c:2053 [inline]
 shmem_write_begin+0x16e/0x4e0 mm/shmem.c:2540
 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3754
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3882
 generic_file_write_iter+0xab/0x310 mm/filemap.c:3914
 call_write_iter include/linux/fs.h:2205 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7ae/0xba0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd0011dcbf2
Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffcacf596b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd0011dcbf2
RDX: 0000000000000083 RSI: 000055bafda89c50 RDI: 0000000000000003
RBP: 000055bafda89c50 R08: 0000000000000001 R09: 0000000000000000
R10: 00007fd00137b3a3 R11: 0000000000000246 R12: 0000000000000083
R13: 00007fd001088300 R14: 0000000000000004 R15: 000055bafda89a60
 </TASK>

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/07/02 06:40 linux-6.1.y 0f4ac6b4c5f0 bfc47836 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in io_ring_exit_work
2023/07/02 06:39 linux-6.1.y 0f4ac6b4c5f0 bfc47836 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in io_ring_exit_work
2023/04/15 13:20 linux-6.1.y 0102425ac76b ec410564 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in io_ring_exit_work
2023/04/03 03:41 linux-6.1.y 3b29299e5f60 f325deb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in io_ring_exit_work
2023/07/02 09:33 linux-6.1.y 0f4ac6b4c5f0 bfc47836 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in io_ring_exit_work
2023/07/02 07:30 linux-6.1.y 0f4ac6b4c5f0 bfc47836 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in io_ring_exit_work
2023/06/11 07:53 linux-6.1.y 2f3918bc53fb 49519f06 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in io_ring_exit_work
2023/05/24 08:59 linux-6.1.y fa74641fb6b9 4bce1a3e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in io_ring_exit_work
* Struck through repros no longer work on HEAD.