INFO: task hung in tracing_open_pipe

Status: upstream: reported syz repro on 2026/08/29 06:04
Reported-by: syzbot+857edde66ea0c015ee10@syzkaller.appspotmail.com
First crash: 30d, last: 28d

Sample crash report:
INFO: task syz.0.17:4502 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:26688 pid:4502  ppid:4399   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_pipe+0x82/0x820 kernel/trace/trace.c:6681
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3834
 do_filp_open+0x1ee/0x420 fs/namei.c:3861
 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: 0033:0x7fd4f4b9e159
RSP: 002b:00007ffd6268ca38 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fd4f4e25fa0 RCX: 00007fd4f4b9e159
RDX: 0000000000000000 RSI: 0000200000000500 RDI: ffffffffffffff9c
RBP: 00007fd4f4c35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd4f4e25fac R14: 00007fd4f4e25fa0 R15: 00007fd4f4e25fa0
 </TASK>
INFO: task syz.3.20:4505 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20        state:D stack:26736 pid:4505  ppid:4405   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_pipe+0x82/0x820 kernel/trace/trace.c:6681
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3834
 do_filp_open+0x1ee/0x420 fs/namei.c:3861
 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: 0033:0x7fd14c99e159
RSP: 002b:00007ffdc8a606d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fd14cc25fa0 RCX: 00007fd14c99e159
RDX: 0000000000000000 RSI: 0000200000000500 RDI: ffffffffffffff9c
RBP: 00007fd14ca35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd14cc25fac R14: 00007fd14cc25fa0 R15: 00007fd14cc25fa0
 </TASK>
INFO: task syz.1.18:4509 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18        state:D stack:26736 pid:4509  ppid:4404   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_pipe+0x82/0x820 kernel/trace/trace.c:6681
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3834
 do_filp_open+0x1ee/0x420 fs/namei.c:3861
 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: 0033:0x7fc6b299e159
RSP: 002b:00007ffeee859648 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc6b2c25fa0 RCX: 00007fc6b299e159
RDX: 0000000000000000 RSI: 0000200000000500 RDI: ffffffffffffff9c
RBP: 00007fc6b2a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc6b2c25fac R14: 00007fc6b2c25fa0 R15: 00007fc6b2c25fa0
 </TASK>
INFO: task syz.4.21:4511 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21        state:D stack:26672 pid:4511  ppid:4406   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_pipe+0x82/0x820 kernel/trace/trace.c:6681
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3834
 do_filp_open+0x1ee/0x420 fs/namei.c:3861
 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: 0033:0x7f77afd9e159
RSP: 002b:00007ffe24587cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f77b0025fa0 RCX: 00007f77afd9e159
RDX: 0000000000000000 RSI: 0000200000000500 RDI: ffffffffffffff9c
RBP: 00007f77afe35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f77b0025fac R14: 00007f77b0025fa0 R15: 00007f77b0025fa0
 </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
5 locks held by kworker/u4:3/46:
3 locks held by kworker/u4:4/57:
2 locks held by kworker/0:2/130:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90002e17d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/0:3/3600:
 #0: ffff88814c2c3938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000f1bfd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd5c4e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4138
3 locks held by kworker/1:3/3655:
 #0: ffff88814c2c3938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003297d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd5c4e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4138
2 locks held by getty/4027:
 #0: ffff88814cf73098 (&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/u4:6/4426:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003327d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd5c4e8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
4 locks held by syz.2.19/4446:
1 lock held by syz.0.17/4502:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.3.20/4505:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.1.18/4509:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.4.21/4511:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.5.22/4533:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.6.23/4592:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.7.24/4599:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.8.25/4624:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.9.26/4625:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.0.35/4700:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.3.39/4715:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.1.45/4722:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.4.46/4735:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.5.75/4786:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.6.83/4820:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.7.86/4853:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.8.92/4857:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz.9.108/4888:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
1 lock held by syz-executor/4908:
 #0: ffffffff8dd5c4e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd5c4e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
1 lock held by syz.0.120/4925:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
8 locks held by syz-executor/4936:
 #0: ffff88807e76c460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
 #1: ffff88804aeaf088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1d8/0x520 fs/kernfs/file.c:343
 #2: ffff8880242710f0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff8880242710f0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x520 fs/kernfs/file.c:344
 #3: ffffffff8d66aba8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd3/0x370 drivers/net/netdevsim/bus.c:209
 #4: ffff88801fb370e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #4: ffff88801fb370e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1099 [inline]
 #4: ffff88801fb370e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb1/0x7c0 drivers/base/dd.c:1302
 #5: ffff88802df532f8 (&devlink->lock_key#16){+.+.}-{3:3}, at: nsim_drv_remove+0x54/0x170 drivers/net/netdevsim/dev.c:1678
 #6: ffffffff8dd5c4e8 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x3b/0x150 drivers/net/netdevsim/netdev.c:381
 #7: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #7: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.3.128/4943:
 #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_pipe+0x82/0x820 kernel/trace/trace.c:6681
6 locks held by syz.2.155/4957:
 #0: ffff88807ea9e460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
 #1: ffff88804e211c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1d8/0x520 fs/kernfs/file.c:343
 #2: ffffffff8cb56648 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
 #2: ffffffff8cb56648 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xe5/0x220 kernel/cgroup/cgroup.c:1700
 #3: ffffffff8c9ca530 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2476 [inline]
 #3: ffffffff8c9ca530 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x186/0x610 kernel/cgroup/cgroup.c:2983
 #4: ffffffff8cb56830 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2478 [inline]
 #4: ffffffff8cb56830 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x19c/0x610 kernel/cgroup/cgroup.c:2983
 #5: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #5: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962

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

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: 4936 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:6004 [inline]
RIP: 0010:zap_class+0x124/0x7f0 kernel/locking/lockdep.c:6050
Code: 3d 04 00 00 48 89 44 24 08 4c 8d 3c c5 80 31 68 90 4c 89 f8 48 c1 e8 03 42 80 3c 30 00 74 08 4c 89 ff e8 6f 58 6e 00 4d 8b 3f <4d> 85 ff 74 c1 49 83 c7 f8 74 bb 4d 89 fd 49 c1 ed 03 43 0f b6 44
RSP: 0018:ffffc900051df538 EFLAGS: 00000046
RAX: 1ffffffff20e80a0 RBX: 0000000000000b08 RCX: 000000000000c31c
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8fa7373a
RBP: 000000000001863c R08: ffffffff90b133a7 R09: 1ffffffff2162674
R10: dffffc0000000000 R11: fffffbfff2162675 R12: 000000000000c31e
R13: 1ffffffff216fe7c R14: dffffc0000000000 R15: 0000000000000000
FS:  0000555557c6a500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f377e670050 CR3: 000000004a74b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __lockdep_free_key_range kernel/locking/lockdep.c:6176 [inline]
 lockdep_unregister_key+0x39b/0x550 kernel/locking/lockdep.c:6378
 __qdisc_destroy+0x128/0x430 net/sched/sch_generic.c:1081
 qdisc_put net/sched/sch_generic.c:1107 [inline]
 dev_shutdown+0x351/0x440 net/sched/sch_generic.c:1468
 unregister_netdevice_many_notify+0xa7e/0x1990 net/core/dev.c:11014
 unregister_netdevice_many net/core/dev.c:11077 [inline]
 unregister_netdevice_queue+0x2e5/0x330 net/core/dev.c:10960
 unregister_netdevice include/linux/netdevice.h:3077 [inline]
 nsim_destroy+0x49/0x150 drivers/net/netdevsim/netdev.c:382
 __nsim_dev_port_del+0x155/0x1c0 drivers/net/netdevsim/dev.c:1433
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1445 [inline]
 nsim_dev_reload_destroy+0x283/0x480 drivers/net/netdevsim/dev.c:1663
 nsim_drv_remove+0x5c/0x170 drivers/net/netdevsim/dev.c:1679
 device_remove drivers/base/dd.c:547 [inline]
 __device_release_driver drivers/base/dd.c:1279 [inline]
 device_release_driver_internal+0x47d/0x7c0 drivers/base/dd.c:1305
 bus_remove_device+0x2dd/0x400 drivers/base/bus.c:531
 device_del+0x63f/0xa80 drivers/base/core.c:3900
 device_unregister+0x1c/0xc0 drivers/base/core.c:3943
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:310 [inline]
 del_device_store+0x2b2/0x370 drivers/net/netdevsim/bus.c:219
 kernfs_fop_write_iter+0x3a0/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2271 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x482/0x9a0 fs/read_write.c:584
 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: 0033:0x7f518ed5e98e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffdcb389dc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555557c6a500 RCX: 00007f518ed5e98e
RDX: 0000000000000001 RSI: 00007ffdcb389e50 RDI: 0000000000000005
RBP: 00007f518ee358a7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffdcb389e50 R14: 00007f518fb54620 R15: 0000000000000003
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/31 06:45 linux-6.1.y d64a499eea6b 2f52988a .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in tracing_open_pipe
2026/08/29 06:03 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in tracing_open_pipe
* Struck through repros no longer work on HEAD.