[v6.1] INFO: task hung in register_trace_uprobe

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e4f7d8be268e Linux 6.1.182
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10ce4a25580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=353a7a3a0b8dee24818e
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/156843a60452/disk-e4f7d8be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/719d532a0151/vmlinux-e4f7d8be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/12160bc2f9ec/bzImage-e4f7d8be.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+353a7a...@syzkaller.appspotmail.com

INFO: task syz.4.2103:12446 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.2103 state:D
stack:24496 pid:12446 ppid:7872 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
register_trace_uprobe+0x2e/0x12f0 kernel/trace/trace_uprobe.c:498
__trace_uprobe_create+0xa41/0xbd0 kernel/trace/trace_uprobe.c:705
trace_probe_create+0xc4/0x130 kernel/trace/trace_probe.c:1243
dyn_event_create+0x44/0x60 kernel/trace/trace_dynevent.c:137
create_or_delete_trace_uprobe+0x61/0x90 kernel/trace/trace_uprobe.c:735
trace_parse_run_command+0x1a8/0x2c0 kernel/trace/trace.c:10258
vfs_write+0x2dc/0x9a0 fs/read_write.c:582
ksys_write+0x14d/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f11fd19e0d9
RSP: 002b:00007f11fe0eb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f11fd425fa0 RCX: 00007f11fd19e0d9
RDX: 000000000000000f RSI: 0000200000000180 RDI: 0000000000000008
RBP: 00007f11fd235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f11fd426038 R14: 00007f11fd425fa0 R15: 00007ffe85458868
</TASK>
INFO: task syz.4.2103:12449 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.2103 state:D stack:27920 pid:12449 ppid:7872 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
trace_array_get kernel/trace/trace.c:461 [inline]
tracing_check_open_get_tr kernel/trace/trace.c:511 [inline]
tracing_open_file_tr+0xab/0x2f0 kernel/trace/trace.c:4892
do_dentry_open+0x7dd/0x10b0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x2674/0x2f10 fs/namei.c:3791
do_filp_open+0x1ee/0x420 fs/namei.c:3818
do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f11fd19e0d9
RSP: 002b:00007f11fe0ca028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f11fd426090 RCX: 00007f11fd19e0d9
RDX: 0000000000000001 RSI: 0000200000000200 RDI: ffffffffffffff9c
RBP: 00007f11fd235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f11fd426128 R14: 00007f11fd426090 R15: 00007ffe85458868
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
2 locks held by getty/4029:
#0: ffff88814d51f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
3 locks held by kworker/0:5/4319:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004467d00 (set_printk_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb82e28 (event_mutex){+.+.}-{3:3}, at: __ftrace_set_clr_event kernel/trace/trace_events.c:1219 [inline]
#2: ffffffff8cb82e28 (event_mutex){+.+.}-{3:3}, at: trace_set_clr_event+0xbe/0x130 kernel/trace/trace_events.c:1285
2 locks held by syz-executor/8660:
3 locks held by kworker/u4:20/9757:
4 locks held by syz.2.2098/12425:
4 locks held by syz.4.2103/12446:
#0: ffff888017794fe8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff8881442a0460 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cb95928 (dyn_event_ops_mutex){+.+.}-{3:3}, at: dyn_event_create+0x1c/0x60 kernel/trace/trace_dynevent.c:136
#3: ffffffff8cb82e28 (event_mutex){+.+.}-{3:3}, at: register_trace_uprobe+0x2e/0x12f0 kernel/trace/trace_uprobe.c:498
1 lock held by syz.4.2103/12449:
#0: ffffffff8cb77748 (trace_types_lock){+.+.}-{3:3}, at: trace_array_get kernel/trace/trace.c:461 [inline]
#0: ffffffff8cb77748 (trace_types_lock){+.+.}-{3:3}, at: tracing_check_open_get_tr kernel/trace/trace.c:511 [inline]
#0: ffffffff8cb77748 (trace_types_lock){+.+.}-{3:3}, at: tracing_open_file_tr+0xab/0x2f0 kernel/trace/trace.c:4892
1 lock held by syz.5.2287/13273:
#0: ffffffff8cb77748 (trace_types_lock){+.+.}-{3:3}, at: trace_array_get kernel/trace/trace.c:461 [inline]
#0: ffffffff8cb77748 (trace_types_lock){+.+.}-{3:3}, at: tracing_check_open_get_tr kernel/trace/trace.c:511 [inline]
#0: ffffffff8cb77748 (trace_types_lock){+.+.}-{3:3}, at: tracing_open_file_tr+0xab/0x2f0 kernel/trace/trace.c:4892
3 locks held by kworker/u4:22/14686:
2 locks held by cmp/15256:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 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+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 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: 12425 Comm: syz.2.2098 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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_cmp8+0x4/0x80 kernel/kcov.c:320
Code: 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 48 8b 04 24 <65> 48 8b 0d 34 3d 80 7e 65 8b 15 35 3d 80 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900042572b8 EFLAGS: 00000293
RAX: ffffffff8a2142c6 RBX: 0000000000000030 RCX: 0000000000080000
RDX: ffffc9000ce79000 RSI: 0000000000000002 RDI: 0000000000000018
RBP: ffffc900042573e0 R08: ffffc90004257357 R09: ffffc90004257340
R10: dffffc0000000000 R11: fffff5200084ae6b R12: ffffc900042576ca
R13: dffffc0000000000 R14: ffffc900042576ca R15: 0000000000000002
FS: 00007f3f31e2a6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f060a0e8286 CR3: 000000007b6d8000 CR4: 00000000003506f0
Call Trace:
<TASK>
number+0xb26/0xef0 lib/vsprintf.c:561
vsnprintf+0x12d3/0x1c20 lib/vsprintf.c:2871
sprintf+0xe4/0x140 lib/vsprintf.c:3009
print_time kernel/printk/printk.c:1274 [inline]
info_print_prefix+0x168/0x360 kernel/printk/printk.c:1300
record_print_text+0x17e/0x4a0 kernel/printk/printk.c:1349
console_emit_next_record+0x5a4/0xb50 kernel/printk/printk.c:2760
console_flush_all kernel/printk/printk.c:-1 [inline]
console_unlock+0x223/0x630 kernel/printk/printk.c:2906
vprintk_emit+0x4b3/0x6a0 kernel/printk/printk.c:2303
_printk+0xda/0x130 kernel/printk/printk.c:2328
event_subsystem_dir kernel/trace/trace_events.c:2490 [inline]
event_create_dir+0xbfe/0xe50 kernel/trace/trace_events.c:2582
__trace_add_new_event kernel/trace/trace_events.c:2986 [inline]
__trace_add_event_dirs kernel/trace/trace_events.c:3200 [inline]
event_trace_add_tracer+0x19b/0x3a0 kernel/trace/trace_events.c:3799
trace_array_create_dir+0x77/0x120 kernel/trace/trace.c:9431
trace_array_create+0x724/0xcb0 kernel/trace/trace.c:9489
instance_mkdir+0xc8/0x120 kernel/trace/trace.c:9524
tracefs_syscall_mkdir+0xb7/0x110 fs/tracefs/inode.c:87
vfs_mkdir+0x386/0x570 fs/namei.c:4114
do_mkdirat+0x1d8/0x440 fs/namei.c:4139
__do_sys_mkdirat fs/namei.c:4154 [inline]
__se_sys_mkdirat fs/namei.c:4152 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4152
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3f30f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3f31e2a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f3f31225fa0 RCX: 00007f3f30f9e0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f3f31035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3f31226038 R14: 00007f3f31225fa0 R15: 00007fff4f0be938
</TASK>


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