INFO: task hung in remove_one

Status: upstream: reported syz repro on 2026/08/02 05:11
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+2c544ba85ab929d6af8b@syzkaller.appspotmail.com
First crash: 87d, last: 19d
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2026/09/23 linux-6.6.y (ToT) 79643295eba1 syz [report] INFO: task hung in remove_one
2026/08/05 upstream (ToT) c21bb4193868 syz [report] INFO: task hung in remove_one
2026/09/23 upstream (ToT) fe2ec83746e5 syz Didn't crash
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in remove_one prio:low fs driver-core 1 syz error 336 1d09h 660d 27/29 upstream: reported syz repro on 2025/01/06 11:11
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2026/09/03 20:34 4h45m bisect fix linux-6.6.y OK (0) job log log

Sample crash report:
INFO: task kworker/u4:3:49 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:3    state:D stack:23752 pid:49    ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0xc1/0x2d0 kernel/time/timer.c:2144
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x2c6/0x5a0 kernel/sched/completion.c:148
 __debugfs_file_removed fs/debugfs/inode.c:748 [inline]
 remove_one+0xe8/0x130 fs/debugfs/inode.c:754
 simple_recursive_removal+0x613/0x7e0 fs/libfs.c:633
 debugfs_remove+0x56/0x70 fs/debugfs/inode.c:777
 nsim_dev_health_exit+0x41/0xc0 drivers/net/netdevsim/health.c:281
 nsim_dev_reload_destroy+0x2ba/0x480 drivers/net/netdevsim/dev.c:1665
 nsim_dev_reload_down+0x8a/0xc0 drivers/net/netdevsim/dev.c:968
 devlink_reload+0x150/0x600 net/devlink/dev.c:389
 devlink_pernet_pre_exit+0x197/0x360 net/devlink/core.c:288
 ops_pre_exit_list net/core/net_namespace.c:163 [inline]
 cleanup_net+0x581/0xb00 net/core/net_namespace.c:636
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
INFO: task syz-executor:5896 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21576 pid:5896  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1676
 device_remove drivers/base/dd.c:626 [inline]
 __device_release_driver drivers/base/dd.c:1351 [inline]
 device_release_driver_internal+0x408/0x6f0 drivers/base/dd.c:1374
 bus_remove_device+0x43b/0x520 drivers/base/bus.c:624
 device_del+0x51f/0x910 drivers/base/core.c:3956
 device_unregister+0x20/0xc0 drivers/base/core.c:3997
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:310 [inline]
 del_device_store+0x2b6/0x370 drivers/net/netdevsim/bus.c:219
 kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc9e315ea0e
RSP: 002b:00007ffdb346cc38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055556f0f4500 RCX: 00007fc9e315ea0e
RDX: 0000000000000001 RSI: 00007ffdb346ccc0 RDI: 0000000000000005
RBP: 00007fc9e323610b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffdb346ccc0 R14: 00007fc9e3f54620 R15: 0000000000000003
 </TASK>
INFO: task syz-executor:5900 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22040 pid:5900  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
 kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f27a3f5ea0e
RSP: 002b:00007ffd7a341d58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555594f2c500 RCX: 00007f27a3f5ea0e
RDX: 0000000000000001 RSI: 00007ffd7a341de0 RDI: 0000000000000005
RBP: 00007f27a403610b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd7a341de0 R14: 00007f27a4d54620 R15: 0000000000000003
 </TASK>
INFO: task syz-executor:5903 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22344 pid:5903  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
 kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd46e95ea0e
RSP: 002b:00007ffeffb24318 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055556c1db500 RCX: 00007fd46e95ea0e
RDX: 0000000000000001 RSI: 00007ffeffb243a0 RDI: 0000000000000005
RBP: 00007fd46ea3610b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffeffb243a0 R14: 00007fd46f754620 R15: 0000000000000003
 </TASK>
INFO: task syz.2.19:5939 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:27880 pid:5939  ppid:5904   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 devlink_health_report+0x33f/0x920 net/devlink/health.c:625
 nsim_dev_health_break_write+0x196/0x230 drivers/net/netdevsim/health.c:216
 full_proxy_write+0x110/0x1c0 fs/debugfs/file.c:244
 vfs_write+0x299/0x9a0 fs/read_write.c:582
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3ef279e1d9
RSP: 002b:00007f3ef1dfe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3ef2a25fa0 RCX: 00007f3ef279e1d9
RDX: 0000000000000003 RSI: 0000200000000340 RDI: 0000000000000003
RBP: 00007f3ef2835888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3ef2a26038 R14: 00007f3ef2a25fa0 R15: 00007fffdbbded28
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8df320e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8df320e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8df320e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6669
5 locks held by kworker/u4:3/49:
 #0: ffff88801ae5d138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #0: ffff88801ae5d138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #1: ffffc90000b9fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #1: ffffc90000b9fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #2: ffffffff8f1c5810 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x140/0xb00 net/core/net_namespace.c:610
 #3: ffff88802230b250 (&devlink->lock_key){+.+.}-{3:3}, at: devl_lock net/devlink/core.c:60 [inline]
 #3: ffff88802230b250 (&devlink->lock_key){+.+.}-{3:3}, at: devlink_pernet_pre_exit+0xee/0x360 net/devlink/core.c:285
 #4: ffff888073326ef0 (&sb->s_type->i_mutex_key#3/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline]
 #4: ffff888073326ef0 (&sb->s_type->i_mutex_key#3/2){+.+.}-{3:3}, at: simple_recursive_removal+0x319/0x7e0 fs/libfs.c:625
2 locks held by kworker/u4:11/3514:
 #0: ffff8880b8c3c258 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559
 #1: ffff8880b8c28a00 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
 #1: ffff8880b8c28a00 (psi_seq){-.-.}-{0:0}, at: __schedule+0x21d3/0x4660 kernel/sched/core.c:6696
2 locks held by getty/5534:
 #0: ffff88802e1b40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032862f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217
6 locks held by syz-executor/5896:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff88806001a888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
 #4: ffff88802230a130 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1094 [inline]
 #4: ffff88802230a130 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1174 [inline]
 #4: ffff88802230a130 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa7/0x6f0 drivers/base/dd.c:1371
 #5: ffff88802230b250 (&devlink->lock_key){+.+.}-{3:3}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1676
4 locks held by syz-executor/5900:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff88802db89888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/5903:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff88805cc43488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
3 locks held by syz.2.19/5939:
 #0: ffff88802229eac8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040
 #1: ffff88814266a418 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #2: ffff88802230b250 (&devlink->lock_key){+.+.}-{3:3}, at: devlink_health_report+0x33f/0x920 net/devlink/health.c:625
4 locks held by syz-executor/5945:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff88802f878c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/5966:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff88807b2c7888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/5967:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff8880741f3c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/5986:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff888060fa8488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/5995:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff888026a3d488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/6012:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff88805ec01c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/6015:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff88805f09a088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/6031:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff888056517488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
4 locks held by syz-executor/6046:
 #0: ffff888032780418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #1: ffff888058da6888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888142b6a6d0 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8eab8268 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209
2 locks held by dhcpcd/6062:
 #0: ffff88805c27c130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1780 [inline]
 #0: ffff88805c27c130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd40 net/packet/af_packet.c:3288
 #1: ffffffff8df37ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #1: ffffffff8df37ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 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+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf59/0xfa0 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 34 Comm: kworker/u4:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:hlock_class kernel/locking/lockdep.c:223 [inline]
RIP: 0010:__lock_acquire+0x1331/0x7eb0 kernel/locking/lockdep.c:5168
Code: 00 00 74 12 48 89 df e8 5d c0 77 00 49 b8 00 00 00 00 00 fc ff df 48 83 3b 00 0f 84 af 06 00 00 48 8b 44 24 50 42 0f b6 04 00 <84> c0 0f 85 24 0d 00 00 41 8b 07 89 c3 81 e3 ff 1f 00 00 c1 e8 03
RSP: 0018:ffffc90000aaf380 EFLAGS: 00000082
RAX: 0000000000000000 RBX: ffffffff91959c20 RCX: ffffffff8168afe2
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff91ff1500
RBP: ffffc90000aaf5c8 R08: dffffc0000000000 R09: 1ffffffff23fe2a0
R10: dffffc0000000000 R11: fffffbfff23fe2a1 R12: 00000000c92e0ee2
R13: ffff8880196e9e00 R14: 00000000125f738a R15: ffff8880196ea9d0
FS:  0000000000000000(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562bb2b7cc70 CR3: 000000000dd32000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 __pte_offset_map+0x48/0x280 mm/pgtable-generic.c:287
 __pte_offset_map_lock+0x47/0x1d0 mm/pgtable-generic.c:371
 get_locked_pte include/linux/mm.h:2741 [inline]
 __text_poke+0x2a4/0xb40 arch/x86/kernel/alternative.c:2036
 text_poke arch/x86/kernel/alternative.c:2121 [inline]
 text_poke_bp_batch+0x249/0x980 arch/x86/kernel/alternative.c:2429
 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_disable_cpuslocked+0xc5/0x1a0 kernel/jump_label.c:237
 static_key_disable+0x1a/0x20 kernel/jump_label.c:245
 toggle_allocation_gate+0x1cc/0x260 mm/kfence/core.c:852
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/09 14:56 linux-6.6.y a91a6aa9253c b2734a59 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in remove_one
2026/08/02 08:26 linux-6.6.y a1153c0deb44 e611ffe1 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in remove_one
2026/10/09 01:27 linux-6.6.y a91a6aa9253c b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in remove_one
2026/08/02 05:10 linux-6.6.y a1153c0deb44 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in remove_one
* Struck through repros no longer work on HEAD.