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: 165d, last: 1d23h
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 64d 87d 0/28 upstream: reported C repro on 2024/11/18 06:32
android-414 INFO: task hung in _free_event 8 2057d 2124d 0/1 auto-closed as invalid on 2019/10/26 01:49
linux-4.19 INFO: task hung in _free_event 1 1741d 1741d 0/1 auto-closed as invalid on 2020/09/05 20:32
linux-4.14 INFO: task hung in _free_event 1 1615d 1615d 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-executor275:7111 blocked for more than 143 seconds.
      Not tainted 6.1.128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor275 state:D stack:27016 pid:7111  ppid:4257   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 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
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa3b17ddab9
RSP: 002b:00007ffec05780a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fa3b17ddab9
RDX: 00007fa3b17ddab9 RSI: 00000000ffffffff RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffec05780bc
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32b290 (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: ffffffff8d32ba90 (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/28:
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510
2 locks held by getty/4001:
 #0: ffff88814ce13098 (&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+0x6a7/0x1db0 drivers/tty/n_tty.c:2198

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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+0x1ae/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+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: 51 Comm: kworker/u4:3 Not tainted 6.1.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:244 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x80 kernel/kcov.c:313
Code: 89 f8 89 f6 49 ff c2 4c 89 11 48 c7 44 0a 08 03 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 c3 0f 1f 00 4c 8b 04 24 <65> 48 8b 15 34 cf 77 7e 65 8b 05 35 cf 77 7e 25 00 01 ff 00 74 10
RSP: 0018:ffffc90000bc78e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90000bc79e8 RCX: ffff88801f2fd940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8ab0b887 R09: ffffffff8ab08a64
R10: 0000000000000002 R11: ffff88801f2fd940 R12: 1ffff92000178f3a
R13: ffffc90000bc7980 R14: ffffc90000bc79d2 R15: 1ffff92000178f3d
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f1884e7618 CR3: 000000000d08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 insn_get_length arch/x86/lib/insn.c:708 [inline]
 insn_decode+0x377/0x500 arch/x86/lib/insn.c:747
 text_poke_loc_init+0xd2/0x680 arch/x86/kernel/alternative.c:1638
 arch_jump_label_transform_queue+0x71/0xd0 arch/x86/kernel/jump_label.c:138
 __jump_label_update+0x177/0x3a0 kernel/jump_label.c:510
 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:818
 process_one_work+0x8a9/0x11d0 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: 1.054 msecs

Crashes (100):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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
2025/02/11 14:31 linux-6.1.y 0cbb5f65e52f 43f51a00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/08 01:33 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/07 07:56 linux-6.1.y 0cbb5f65e52f 53657d1b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/05 01:51 linux-6.1.y 0cbb5f65e52f 5896748e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/03 07:49 linux-6.1.y 0cbb5f65e52f 568559e4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/01 18:18 linux-6.1.y 75cefdf153f5 aa47157c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/02/01 03:32 linux-6.1.y 75cefdf153f5 aa47157c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/31 13:49 linux-6.1.y 75cefdf153f5 4c6ac32f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/28 08:50 linux-6.1.y 75cefdf153f5 18070896 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/28 06:30 linux-6.1.y 75cefdf153f5 18070896 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/28 04:00 linux-6.1.y 75cefdf153f5 18070896 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/27 16:20 linux-6.1.y 75cefdf153f5 d99a33ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/24 22:26 linux-6.1.y 75cefdf153f5 1293872d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/24 18:47 linux-6.1.y 75cefdf153f5 1293872d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/21 18:58 linux-6.1.y f4f677285b38 da72ac06 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/20 10:11 linux-6.1.y f4f677285b38 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/18 05:39 linux-6.1.y 60ceadf9247e f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/17 17:20 linux-6.1.y 60ceadf9247e 953d1c45 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/16 17:52 linux-6.1.y c63962be84ef f9e07a6e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/14 19:31 linux-6.1.y c63962be84ef f310a27d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/14 02:44 linux-6.1.y c63962be84ef b1f1cd88 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/13 05:39 linux-6.1.y c63962be84ef 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/11 04:57 linux-6.1.y c63962be84ef 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/10 22:33 linux-6.1.y c63962be84ef 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/10 20:41 linux-6.1.y c63962be84ef 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/09 15:42 linux-6.1.y c63962be84ef 9220929f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/08 14:55 linux-6.1.y 7dc732d24ff7 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/07 13:29 linux-6.1.y 7dc732d24ff7 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/06 12:24 linux-6.1.y 7dc732d24ff7 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2025/01/02 23:38 linux-6.1.y 7dc732d24ff7 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/28 08:19 linux-6.1.y 563edd786f0a d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/28 06:57 linux-6.1.y 563edd786f0a d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/22 13:08 linux-6.1.y 29f02ec58a94 b4fbdbd4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/19 05:28 linux-6.1.y 52f863f820fd 1432fc84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/16 13:42 linux-6.1.y 52f863f820fd eec85da6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/15 13:34 linux-6.1.y 52f863f820fd 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/15 02:43 linux-6.1.y 52f863f820fd 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/13 23:16 linux-6.1.y e4d90d63d385 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/13 02:02 linux-6.1.y e4d90d63d385 530e80f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/12 19:23 linux-6.1.y e4d90d63d385 530e80f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/09 19:31 linux-6.1.y e4d90d63d385 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/12/04 20:42 linux-6.1.y e4d90d63d385 b50eb251 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/11/29 19:57 linux-6.1.y e4d90d63d385 5df23865 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/11/28 21:48 linux-6.1.y e4d90d63d385 5df23865 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/11/27 10:51 linux-6.1.y e4d90d63d385 52b38cc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/11/27 05:35 linux-6.1.y e4d90d63d385 52b38cc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in _free_event
2024/11/22 07:41 linux-6.1.y b67dc5c9ade9 4b25d554 .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.