INFO: task hung in ftrace_set_clr_event

Status: upstream: reported syz repro on 2026/08/15 22:42
Subsystems: trace
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+1b4a3085f6696737b17c@syzkaller.appspotmail.com
First crash: 52d, last: 34d
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
4d8134d8 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: task hung in ftrace_set_clr_event 2026/08/12 02:10 2026/08/12 02:10 2026/08/12 02:39 f8d35649
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [trace?] INFO: task hung in ftrace_set_clr_event 0 (1) 2026/08/15 22:42
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/08/30 12:36 25m retest repro upstream report job log log
▶ ▼ Cause bisection attempts (1)
Created Duration User Patch Repo Result
2026/09/20 18:17 0m bisect upstream error

Sample crash report:
INFO: task syz.0.17:6034 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:27496 pid:6034  tgid:6033  ppid:5744   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
 __ftrace_set_clr_event kernel/trace/trace_events.c:1409 [inline]
 ftrace_set_clr_event+0x3ba/0x5c0 kernel/trace/trace_events.c:1460
 ftrace_event_write+0x1fe/0x2b0 kernel/trace/trace_events.c:1548
 vfs_write+0x296/0xba0 fs/read_write.c:685
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc695d9e0d9
RSP: 002b:00007fc696c90028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc696025fa0 RCX: 00007fc695d9e0d9
RDX: 0000000000000002 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007fc695e35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc696026038 R14: 00007fc696025fa0 R15: 00007ffd5a54d898
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
4 locks held by kworker/1:0/24:
 #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc900001e7c40 (reg_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc900001e7c40 (reg_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffffffff90027f40 (rtnl_mutex){+.+.}-{4:4}, at: reg_todo+0x1c/0xa40 net/wireless/reg.c:3205
 #3: ffff88806a4807a0 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6884 [inline]
 #3: ffff88806a4807a0 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: reg_process_self_managed_hints+0x8d/0x160 net/wireless/reg.c:3195
1 lock held by khungtaskd/32:

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/11 22:30 upstream f5bbbfec59b4 37a258dd .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in ftrace_set_clr_event
* Struck through repros no longer work on HEAD.