syzbot

INFO: task kworker/u8:7:1156 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:7    state:D stack:23368 pid:1156  tgid:1156  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121
 __debugfs_file_removed fs/debugfs/inode.c:751 [inline]
 remove_one+0x312/0x420 fs/debugfs/inode.c:758
 __simple_recursive_removal+0x148/0x5c0 fs/libfs.c:623
 debugfs_remove+0x5d/0x80 fs/debugfs/inode.c:781
 nsim_dev_health_exit+0x3b/0xe0 drivers/net/netdevsim/health.c:227
 nsim_dev_reload_destroy+0x144/0x4a0 drivers/net/netdevsim/dev.c:1788
 nsim_dev_reload_down+0x66/0xd0 drivers/net/netdevsim/dev.c:1038
 devlink_reload+0x1ae/0x7a0 net/devlink/dev.c:462
 devlink_pernet_pre_exit+0x247/0x370 net/devlink/core.c:560
 ops_pre_exit_list net/core/net_namespace.c:161 [inline]
 ops_undo_list+0x187/0xab0 net/core/net_namespace.c:234
 cleanup_net+0x499/0x920 net/core/net_namespace.c:702
 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz-executor:8221 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:24072 pid:8221  tgid:8221  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
 device_lock include/linux/device.h:1040 [inline]
 device_del+0xa0/0x9b0 drivers/base/core.c:3857
 device_unregister+0x1d/0xe0 drivers/base/core.c:3936
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:491 [inline]
 del_device_store+0x346/0x480 drivers/net/netdevsim/bus.c:244
 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7ce835d68e
RSP: 002b:00007ffce1b0f878 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055557b8c6500 RCX: 00007f7ce835d68e
RDX: 0000000000000001 RSI: 00007ffce1b0f900 RDI: 0000000000000005
RBP: 00007f7ce84335f2 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffce1b0f900 R14: 00007f7ce9144620 R15: 0000000000000003
 </TASK>
INFO: task syz.3.2277:8238 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.2277      state:D stack:28456 pid:8238  tgid:8238  ppid:5804   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
 devlink_health_report+0x66c/0xb20 net/devlink/health.c:680
 nsim_dev_health_break_write+0x166/0x210 drivers/net/netdevsim/health.c:162
 full_proxy_write+0x135/0x1a0 fs/debugfs/file.c:388
 vfs_write+0x2aa/0x1070 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7fc139ce59
RSP: 002b:00007ffe5d5a7908 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f7fc1615fa0 RCX: 00007f7fc139ce59
RDX: 00000000000001e1 RSI: 0000200000000080 RDI: 0000000000000003
RBP: 00007f7fc1432d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7fc1615fac R14: 00007f7fc1615fa0 R15: 00007f7fc1615fa0
 </TASK>
INFO: task syz.0.2303:8269 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2303      state:D stack:27704 pid:8269  tgid:8269  ppid:5796   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 rwsem_down_read_slowpath+0x5af/0xb40 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0xed/0x450 kernel/locking/rwsem.c:1570
 inode_lock_shared include/linux/fs.h:1044 [inline]
 open_last_lookups fs/namei.c:4607 [inline]
 path_openat+0xb3c/0x4280 fs/namei.c:4856
 do_file_open+0x20e/0x430 fs/namei.c:4888
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1412
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9ee4b9ce59
RSP: 002b:00007ffe4e905dd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9ee4e15fa0 RCX: 00007f9ee4b9ce59
RDX: 0000000000048081 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007f9ee4c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9ee4e15fac R14: 00007f9ee4e15fa0 R15: 00007f9ee4e15fa0
 </TASK>
INFO: task syz.1.2304:8270 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2304      state:D stack:28280 pid:8270  tgid:8270  ppid:5798   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 rwsem_down_read_slowpath+0x5af/0xb40 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0xed/0x450 kernel/locking/rwsem.c:1570
 inode_lock_shared include/linux/fs.h:1044 [inline]
 open_last_lookups fs/namei.c:4607 [inline]
 path_openat+0xb3c/0x4280 fs/namei.c:4856
 do_file_open+0x20e/0x430 fs/namei.c:4888
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1412
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f043399ce59
RSP: 002b:00007ffe973ce948 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0433c15fa0 RCX: 00007f043399ce59
RDX: 0000000000048081 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007f0433a32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0433c15fac R14: 00007f0433c15fa0 R15: 00007f0433c15fa0
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/30:
 #0: ffffffff8e7e56a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e7e56a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8e7e56a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:7/1156:
 #0: ffff88801c6a6140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
 #1: ffffc9000590fd08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
 #2: ffffffff905f23c8 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673
 #3: ffff8880227a5128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
 #3: ffff8880227a5128 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline]
 #3: ffff8880227a5128 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x19e/0x370 net/devlink/core.c:557
 #4: ffff8880227a4258 (&devlink->lock_key#2){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline]
 #4: ffff8880227a4258 (&devlink->lock_key#2){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline]
 #4: ffff8880227a4258 (&devlink->lock_key#2){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x1b4/0x370 net/devlink/core.c:557
 #5: ffff88805b15de20 (&sb->s_type->i_mutex_key#9/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline]
 #5: ffff88805b15de20 (&sb->s_type->i_mutex_key#9/2){+.+.}-{4:4}, at: __simple_recursive_removal+0xe0/0x5c0 fs/libfs.c:619
2 locks held by getty/5389:
 #0: ffff888032e840a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14f0 drivers/tty/n_tty.c:2211
5 locks held by syz-executor/8221:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff88807a922c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
 #4: ffff8880227a5128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
 #4: ffff8880227a5128 (&dev->mutex){....}-{4:4}, at: device_del+0xa0/0x9b0 drivers/base/core.c:3857
2 locks held by syz.3.2277/8238:
 #0: ffff88801feca450 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff8880227a4258 (&devlink->lock_key#2){+.+.}-{4:4}, at: devlink_health_report+0x66c/0xb20 net/devlink/health.c:680
2 locks held by syz.0.2303/8269:
 #0: ffff88801feca450 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:4597 [inline]
 #0: ffff88801feca450 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0xad9/0x4280 fs/namei.c:4856
 #1: ffff88805b15de20 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1044 [inline]
 #1: ffff88805b15de20 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: open_last_lookups fs/namei.c:4607 [inline]
 #1: ffff88805b15de20 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: path_openat+0xb3c/0x4280 fs/namei.c:4856
2 locks held by syz.1.2304/8270:
 #0: ffff88801feca450 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:4597 [inline]
 #0: ffff88801feca450 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0xad9/0x4280 fs/namei.c:4856
 #1: ffff88805b15de20 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1044 [inline]
 #1: ffff88805b15de20 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: open_last_lookups fs/namei.c:4607 [inline]
 #1: ffff88805b15de20 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: path_openat+0xb3c/0x4280 fs/namei.c:4856
4 locks held by syz-executor/8286:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff88805d9c3880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8287:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff88807b973080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8293:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff888033465480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8347:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff888079cff480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8368:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff88807dce5480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8370:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff88807dce7c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8372:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff888072b58880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8434:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff888031ff2480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8455:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff888079e5e880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8458:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff88807a208c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/8460:
 #0: ffff88803655c450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: ffff88807a20b880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff88802a2c21e8 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: ffffffff8fb8be60 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xcb1/0x1030 kernel/hung_task.c:561
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: f6 94 02 e9 43 44 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 a0 23 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df0 EFLAGS: 00000246
RAX: 000000000012f599 RBX: ffff88801e688000 RCX: ffffffff8b87f225
RDX: 0000000000000000 RSI: ffffffff8df1dc45 RDI: ffffffff8c1c6500
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a67b5
R10: ffff8880b8533dab R11: 0000000000000000 R12: 0000000000000001
R13: ffffed1003cd1000 R14: 0000000000000001 R15: ffffffff90d79650
FS:  0000000000000000(0000) GS:ffff888124483000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d41bd30a38 CR3: 000000000e596000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
 default_idle+0x9/0x10 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x464/0x590 kernel/sched/idle.c:352
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x148
 </TASK>