syzbot


INFO: task hung in call_usermodehelper_exec (2)

Status: closed as invalid on 2022/02/08 09:40
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 391d, last: 391d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in call_usermodehelper_exec 1 696d 696d 0/24 auto-closed as invalid on 2021/04/09 04:38

Sample crash report:
INFO: task kworker/0:7:28535 blocked for more than 143 seconds.
      Not tainted 5.15.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:7     state:D stack:22800 pid:28535 ppid:     2 flags:0x00004000
Workqueue: events cgroup1_release_agent
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4969 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6250
 schedule+0x12b/0x1f0 kernel/sched/core.c:6323
 schedule_timeout+0xac/0x300 kernel/time/timer.c:1857
 do_wait_for_common+0x2da/0x480 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
 call_usermodehelper_exec+0x299/0x430 kernel/umh.c:450
 cgroup1_release_agent+0x330/0x3c0 kernel/cgroup/cgroup-v1.c:805
 process_one_work+0x853/0x1140 kernel/workqueue.c:2298
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2445
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>

Showing all locks held in the system:
2 locks held by systemd/1:
1 lock held by kthreadd/2:
1 lock held by khungtaskd/27:
 #0: ffffffff8cb1d900 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by khugepaged/33:
 #0: ffffffff8cbb6288 (lock#5){+.+.}-{3:3}, at: __lru_add_drain_all+0x67/0x9d0 mm/swap.c:797
1 lock held by kswapd0/97:
1 lock held by kswapd1/98:
2 locks held by kworker/u4:5/1041:
 #0: ffff888011469138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7ca/0x1140
 #1: ffffc90004717d20 ((kfence_timer).work){+.+.}-{0:0}, at: process_one_work+0x808/0x1140 kernel/workqueue.c:2273
4 locks held by kworker/1:3/2953:
1 lock held by systemd-journal/2969:
1 lock held by systemd-udevd/2973:
2 locks held by systemd-timesyn/3058:
2 locks held by in:imklog/6227:
 #0: ffff888019b6c370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:990
 #1: ffffffff8cbe1a28 (pcpu_drain_mutex){+.+.}-{3:3}, at: __drain_all_pages+0x58/0x690 mm/page_alloc.c:3181
2 locks held by cron/6206:
2 locks held by syz-fuzzer/6515:
2 locks held by syz-fuzzer/6518:
1 lock held by syz-executor.5/6790:
3 locks held by kworker/0:5/8525:
2 locks held by kworker/0:7/28535:
 #0: ffff888011464d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7ca/0x1140
 #1: ffffc90004757d20 ((work_completion)(&cgrp->release_agent_work)){+.+.}-{0:0}, at: process_one_work+0x808/0x1140 kernel/workqueue.c:2273
1 lock held by syz-executor.1/30907:
1 lock held by systemd-sysctl/30968:
2 locks held by systemd-cgroups/30970:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.0-syzkaller #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+0x1dc/0x2d8 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc82/0xcd0 kernel/hung_task.c:295
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 28188 Comm: kworker/u4:0 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_preemption_disabled+0x6c/0x1c0 lib/smp_processor_id.c:55
Code: 00 00 81 e5 ff ff ff 7f 74 2a 0f 1f 44 00 00 65 48 8b 04 25 28 00 00 00 48 3b 44 24 08 0f 85 52 01 00 00 89 d8 48 83 c4 10 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 24
RSP: 0018:ffffc900028ef5a8 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 1ffff9200051dec0 RCX: 0000000080000002
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000000
RBP: 0000000000000003 R08: dffffc0000000000 R09: fffffbfff1bfa7b6
R10: fffffbfff1bfa7b6 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8ad4b0e0 R15: ffffffff8ad4b0a0
FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa57b06a018 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_lockdep_current_cpu_online+0x36/0x130 kernel/rcu/tree.c:1169
 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
 rcu_read_lock_sched_held+0x74/0x130 kernel/rcu/update.c:123
 trace_tlb_flush+0x7b/0x190 include/trace/events/tlb.h:38
 switch_mm_irqs_off+0x5cf/0x940
 unuse_temporary_mm arch/x86/kernel/alternative.c:946 [inline]
 __text_poke+0x767/0x9f0 arch/x86/kernel/alternative.c:1042
 text_poke arch/x86/kernel/alternative.c:1083 [inline]
 text_poke_bp_batch+0x6b0/0x940 arch/x86/kernel/alternative.c:1361
 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x12d/0x250 kernel/jump_label.c:177
 static_key_enable+0x16/0x20 kernel/jump_label.c:190
 toggle_allocation_gate+0xbf/0x460 mm/kfence/core.c:732
 process_one_work+0x853/0x1140 kernel/workqueue.c:2298
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2445
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	81 e5 ff ff ff 7f    	and    $0x7fffffff,%ebp
   8:	74 2a                	je     0x34
   a:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
   f:	65 48 8b 04 25 28 00 	mov    %gs:0x28,%rax
  16:	00 00
  18:	48 3b 44 24 08       	cmp    0x8(%rsp),%rax
  1d:	0f 85 52 01 00 00    	jne    0x175
  23:	89 d8                	mov    %ebx,%eax
  25:	48 83 c4 10          	add    $0x10,%rsp
  29:	5b                   	pop    %rbx
* 2a:	41 5c                	pop    %r12 <-- trapping instruction
  2c:	41 5d                	pop    %r13
  2e:	41 5e                	pop    %r14
  30:	41 5f                	pop    %r15
  32:	5d                   	pop    %rbp
  33:	c3                   	retq
  34:	48 c7 04 24 00 00 00 	movq   $0x0,(%rsp)
  3b:	00
  3c:	9c                   	pushfq
  3d:	8f 04 24             	popq   (%rsp)

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/11/10 11:09 upstream cb690f5238d7 55fa030c .config log report info INFO: task hung in call_usermodehelper_exec
* Struck through repros no longer work on HEAD.