syzbot


INFO: task hung in _free_event

Status: upstream: reported C repro on 2024/09/01 12:31
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+3feacdb0b5d7164173e8@syzkaller.appspotmail.com
First crash: 224d, last: 26m
Bug presence (2)
Date Name Commit Repro Result
2024/11/17 linux-6.1.y (ToT) 59d7b1a7104a C [report] INFO: task hung in _free_event
2024/11/17 upstream (ToT) 4a5df3796467 C Didn't crash
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in _free_event perf C 2 123d 146d 19/28 upstream: reported C repro on 2024/11/18 06:32
android-414 INFO: task hung in _free_event 8 2116d 2184d 0/1 auto-closed as invalid on 2019/10/26 01:49
linux-4.19 INFO: task hung in _free_event 1 1800d 1800d 0/1 auto-closed as invalid on 2020/09/05 20:32
linux-4.14 INFO: task hung in _free_event 1 1674d 1674d 0/1 auto-closed as invalid on 2021/01/10 07:54
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2024/12/29 01:42 2h00m fix candidate upstream OK (0) job log

Sample crash report:
INFO: task syz-executor335:4317 blocked for more than 143 seconds.
      Not tainted 6.1.131-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor335 state:D stack:25680 pid:4317  ppid:4261   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 perf_pending_task_sync kernel/events/core.c:5033 [inline]
 _free_event+0x169/0x1090 kernel/events/core.c:5039
 put_event kernel/events/core.c:5164 [inline]
 perf_event_release_kernel+0x873/0x900 kernel/events/core.c:5289
 perf_release+0x37/0x40 kernel/events/core.c:5299
 __fput+0x3f6/0x8d0 fs/file_table.c:320
 task_work_run+0x246/0x300 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0xa6e/0x26a0 kernel/exit.c:871
 do_group_exit+0x202/0x2b0 kernel/exit.c:1021
 __do_sys_exit_group kernel/exit.c:1032 [inline]
 __se_sys_exit_group kernel/exit.c:1030 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1030
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff55bf68c49
RSP: 002b:00007ffe5171daf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff55bf68c49
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007ff55bfe3290 R08: ffffffffffffffb8 R09: 0000000000000006
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ff55bfe3290
R13: 0000000000000000 R14: 00007ff55bfe3ce0 R15: 00007ff55bf39ea0
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32e890 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d32f090 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
 #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510
2 locks held by getty/4003:
 #0: ffff88803059b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x54a/0x1620 drivers/tty/n_tty.c:2198

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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+0x1ca/0x430 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+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 46 Comm: kworker/u4:3 Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:101 [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+0x5c/0x290 mm/kasan/generic.c:189
Code: fb 48 c1 eb 03 49 b8 00 00 00 00 00 fc ff df 4e 8d 0c 03 4c 8d 54 37 ff 49 c1 ea 03 49 bb 01 00 00 00 00 fc ff df 4f 8d 34 1a <4c> 89 f5 4c 29 cd 48 83 fd 10 7f 26 48 85 ed 0f 84 3a 01 00 00 49
RSP: 0018:ffffc90000b77748 EFLAGS: 00000a06
RAX: 0000000000000001 RBX: 1ffff11002f8cc0c RCX: ffffffff816c1884
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888017c66060
RBP: 000000000001ffff R08: dffffc0000000000 R09: ffffed1002f8cc0c
R10: 1ffff11002f8cc0c R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff9200016ef0c R14: ffffed1002f8cc0d R15: ffff888017c66060
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556cbe6c7600 CR3: 000000000d08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 queued_spin_is_locked include/asm-generic/qspinlock.h:57 [inline]
 debug_spin_unlock kernel/locking/spinlock_debug.c:100 [inline]
 do_raw_spin_unlock+0x54/0x8a0 kernel/locking/spinlock_debug.c:140
 __raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_unlock+0x1a/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 __text_poke+0x81a/0x9a0 arch/x86/kernel/alternative.c:1216
 text_poke arch/x86/kernel/alternative.c:1240 [inline]
 text_poke_bp_batch+0x66b/0x940 arch/x86/kernel/alternative.c:1612
 text_poke_flush arch/x86/kernel/alternative.c:1725 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1732
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_disable_cpuslocked+0xce/0x1b0 kernel/jump_label.c:237
 static_key_disable+0x16/0x20 kernel/jump_label.c:245
 toggle_allocation_gate+0x3e0/0x480 mm/kfence/core.c:819
 process_one_work+0x917/0x1260 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.420 msecs

Crashes (192):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/26 09:25 linux-6.1.y 344a09659766 89d30d73 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/24 17:47 linux-6.1.y 344a09659766 875573af .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/20 11:18 linux-6.1.y 344a09659766 9209bc22 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/16 18:48 linux-6.1.y 344a09659766 e2826670 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/15 02:22 linux-6.1.y 344a09659766 e2826670 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/06 20:46 linux-6.1.y 3a8358583626 831e3629 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/06 17:34 linux-6.1.y 3a8358583626 831e3629 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/05 19:57 linux-6.1.y 3a8358583626 60f5d8d9 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/02 21:49 linux-6.1.y 3a8358583626 c3901742 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/10 18:41 linux-6.1.y 0cbb5f65e52f 43f51a00 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/01 04:56 linux-6.1.y 75cefdf153f5 aa47157c .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/01 00:01 linux-6.1.y 75cefdf153f5 aa47157c .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/24 04:47 linux-6.1.y 75cefdf153f5 521b0ce3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/11 22:47 linux-6.1.y c63962be84ef 6dbc6a9b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/01 23:01 linux-6.1.y 563edd786f0a d3ccff63 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/22 16:38 linux-6.1.y 29f02ec58a94 b4fbdbd4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/16 08:14 linux-6.1.y 52f863f820fd 7cbfbb3a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/11/16 15:38 linux-6.1.y 59d7b1a7104a cfe3a04a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/13 19:00 linux-6.1.y 420102835862 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/12 17:59 linux-6.1.y 420102835862 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/12 12:57 linux-6.1.y 420102835862 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/10 20:56 linux-6.1.y 420102835862 1ef3ab4d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/08 14:41 linux-6.1.y 3dfebb87d7eb a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/07 23:30 linux-6.1.y 3dfebb87d7eb a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/07 17:47 linux-6.1.y 3dfebb87d7eb a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/07 05:57 linux-6.1.y 8e60a714ba3b 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/06 03:17 linux-6.1.y 8e60a714ba3b 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/05 23:45 linux-6.1.y 8e60a714ba3b 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/04 13:30 linux-6.1.y 8e60a714ba3b 1c4febdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/04 13:29 linux-6.1.y 8e60a714ba3b 1c4febdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/04 03:38 linux-6.1.y 8e60a714ba3b d7ae3a11 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/03 23:05 linux-6.1.y 8e60a714ba3b d7ae3a11 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/02 17:40 linux-6.1.y 8e60a714ba3b c799dfdd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/02 09:49 linux-6.1.y 8e60a714ba3b c799dfdd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/01 18:07 linux-6.1.y 8e60a714ba3b b8645499 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/04/01 04:32 linux-6.1.y 8e60a714ba3b 36d76a97 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/31 12:54 linux-6.1.y 8e60a714ba3b d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/31 02:16 linux-6.1.y 8e60a714ba3b d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/29 23:19 linux-6.1.y 8e60a714ba3b d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/29 08:34 linux-6.1.y 8e60a714ba3b cf25e2c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/29 07:29 linux-6.1.y 8e60a714ba3b cf25e2c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/29 01:38 linux-6.1.y 8e60a714ba3b 9a1a9e31 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/28 19:34 linux-6.1.y 344a09659766 9a1a9e31 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/28 10:36 linux-6.1.y 344a09659766 6c09fb82 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/27 18:31 linux-6.1.y 344a09659766 6c09fb82 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/26 22:49 linux-6.1.y 344a09659766 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/26 05:38 linux-6.1.y 344a09659766 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/26 01:35 linux-6.1.y 344a09659766 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/25 23:49 linux-6.1.y 344a09659766 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/23 07:53 linux-6.1.y 344a09659766 4e8d3850 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/23 06:34 linux-6.1.y 344a09659766 4e8d3850 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/22 00:57 linux-6.1.y 344a09659766 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/21 00:08 linux-6.1.y 344a09659766 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/18 13:11 linux-6.1.y 344a09659766 ce3352cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/17 00:53 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/15 21:19 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/15 18:20 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/15 15:01 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/15 05:52 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/14 20:33 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/03/14 03:23 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/09/01 12:30 linux-6.1.y 311d8503ef9f 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
* Struck through repros no longer work on HEAD.