syzbot


INFO: task hung in io_uring_alloc_task_context (2)

Status: auto-closed as invalid on 2022/06/09 11:30
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 260d, last: 260d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in io_uring_alloc_task_context 4 314d 374d 0/24 closed as invalid on 2022/02/08 09:40
upstream INFO: task hung in io_uring_alloc_task_context (3) 1 155d 155d 0/24 auto-closed as invalid on 2022/09/22 17:27

Sample crash report:
INFO: task syz-executor.4:28935 blocked for more than 143 seconds.
      Not tainted 5.17.0-rc7-syzkaller-00200-gdda64ead7e82 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:29160 pid:28935 ppid:  3624 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4995 [inline]
 __schedule+0xa94/0x4910 kernel/sched/core.c:6304
 schedule+0xd2/0x260 kernel/sched/core.c:6377
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6436
 __mutex_lock_common kernel/locking/mutex.c:673 [inline]
 __mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:733
 io_init_wq_offload fs/io_uring.c:8717 [inline]
 io_uring_alloc_task_context+0xf9/0x544 fs/io_uring.c:8758
 __io_uring_add_tctx_node.cold+0x19/0x188 fs/io_uring.c:9810
 io_uring_add_tctx_node fs/io_uring.c:9855 [inline]
 __do_sys_io_uring_enter+0x1a47/0x1fc0 fs/io_uring.c:10158
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fab68494049
RSP: 002b:00007fab66dc7168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007fab685a7100 RCX: 00007fab68494049
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: 00007fab684ee08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc0af6f05f R14: 00007fab66dc7300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8bb820a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6460
2 locks held by getty/3278:
 #0: ffff88814af30098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc90002b5e2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2075
2 locks held by syz-executor.4/28930:
1 lock held by syz-executor.4/28935:
 #0: ffff8880738150a8 (&ctx->uring_lock){+.+.}-{3:3}, at: io_init_wq_offload fs/io_uring.c:8717 [inline]
 #0: ffff8880738150a8 (&ctx->uring_lock){+.+.}-{3:3}, at: io_uring_alloc_task_context+0xf9/0x544 fs/io_uring.c:8758

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.17.0-rc7-syzkaller-00200-gdda64ead7e82 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:369
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 13497 Comm: kworker/u4:21 Not tainted 5.17.0-rc7-syzkaller-00200-gdda64ead7e82 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:84 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0xd6/0x180 mm/kasan/generic.c:189
Code: 48 39 d0 74 7a 80 38 00 74 f2 48 89 c2 b8 01 00 00 00 48 85 d2 75 56 5b 5d 41 5c c3 48 85 d2 74 5e 48 01 ea eb 09 48 83 c0 01 <48> 39 d0 74 50 80 38 00 74 f2 eb d4 41 bc 08 00 00 00 48 89 ea 45
RSP: 0018:ffffc90004607b88 EFLAGS: 00000286
RAX: fffffbfff1b27e03 RBX: fffffbfff1b27e03 RCX: ffffffff815cc388
RDX: fffffbfff1b27e03 RSI: 0000000000000008 RDI: ffffffff8d93f010
RBP: fffffbfff1b27e02 R08: 0000000000000000 R09: ffffffff8d93f017
R10: fffffbfff1b27e02 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: ffffffff8bb820a0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ab0477e600 CR3: 000000000b88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 cpumask_test_cpu include/linux/cpumask.h:379 [inline]
 cpu_online include/linux/cpumask.h:921 [inline]
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0xb8/0x510 kernel/locking/lockdep.c:5610
 rcu_lock_acquire include/linux/rcupdate.h:268 [inline]
 rcu_read_lock include/linux/rcupdate.h:694 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0x12d/0xfa0 net/batman-adv/network-coding.c:719
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess):
   0:	48 39 d0             	cmp    %rdx,%rax
   3:	74 7a                	je     0x7f
   5:	80 38 00             	cmpb   $0x0,(%rax)
   8:	74 f2                	je     0xfffffffc
   a:	48 89 c2             	mov    %rax,%rdx
   d:	b8 01 00 00 00       	mov    $0x1,%eax
  12:	48 85 d2             	test   %rdx,%rdx
  15:	75 56                	jne    0x6d
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	41 5c                	pop    %r12
  1b:	c3                   	retq
  1c:	48 85 d2             	test   %rdx,%rdx
  1f:	74 5e                	je     0x7f
  21:	48 01 ea             	add    %rbp,%rdx
  24:	eb 09                	jmp    0x2f
  26:	48 83 c0 01          	add    $0x1,%rax
* 2a:	48 39 d0             	cmp    %rdx,%rax <-- trapping instruction
  2d:	74 50                	je     0x7f
  2f:	80 38 00             	cmpb   $0x0,(%rax)
  32:	74 f2                	je     0x26
  34:	eb d4                	jmp    0xa
  36:	41 bc 08 00 00 00    	mov    $0x8,%r12d
  3c:	48 89 ea             	mov    %rbp,%rdx
  3f:	45                   	rex.RB

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-selinux-root 2022/03/11 11:25 upstream dda64ead7e82 9e8eaa75 .config log report info INFO: task hung in io_uring_alloc_task_context
* Struck through repros no longer work on HEAD.