INFO: task syz-executor:16378 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:22352 pid:16378 tgid:16378 ppid:1      task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16df/0x5510 kernel/sched/core.c:7239
 __schedule_loop kernel/sched/core.c:7316 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7331
 schedule_timeout+0xc0/0x2c0 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x2ca/0x5e0 kernel/sched/completion.c:153
 __debugfs_file_removed fs/debugfs/inode.c:751 [inline]
 remove_one+0x2df/0x3b0 fs/debugfs/inode.c:758
 __simple_recursive_removal+0x215/0x520 fs/libfs.c:623
 debugfs_remove+0x5b/0x70 fs/debugfs/inode.c:781
 nsim_dev_debugfs_exit drivers/net/netdevsim/dev.c:372 [inline]
 nsim_drv_remove+0xc0/0x160 drivers/net/netdevsim/dev.c:1803
 device_remove drivers/base/dd.c:616 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3961
 device_unregister+0x21/0xf0 drivers/base/core.c:4002
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:491 [inline]
 del_device_store+0x2b5/0x370 drivers/net/netdevsim/bus.c:244
 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61e/0xbb0 fs/read_write.c:687
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6191fae90e
RSP: 002b:00007ffd9effc398 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555585925500 RCX: 00007f6191fae90e
RDX: 0000000000000001 RSI: 00007ffd9effc420 RDI: 0000000000000005
RBP: 00007f61920858a7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd9effc420 R14: 00007f6192da4620 R15: 0000000000000003
 </TASK>
INFO: task syz.2.5200:16744 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.5200      state:D stack:28464 pid:16744 tgid:16740 ppid:13414  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16df/0x5510 kernel/sched/core.c:7239
 __schedule_loop kernel/sched/core.c:7316 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7612
 rt_mutex_slowlock_block+0x55e/0x690 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
 full_proxy_write+0x127/0x1f0 fs/debugfs/file.c:388
 vfs_write+0x29f/0xbb0 fs/read_write.c:685
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff4dd0ae0d9
RSP: 002b:00007ff4dc70e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff4dd335fa0 RCX: 00007ff4dd0ae0d9
RDX: 0000000000000001 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007ff4dd145024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff4dd336038 R14: 00007ff4dd335fa0 R15: 00007ffee45aa248
 </TASK>
INFO: task syz.4.5201:16745 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.5201      state:D stack:28368 pid:16745 tgid:16741 ppid:11870  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16df/0x5510 kernel/sched/core.c:7239
 __schedule_loop kernel/sched/core.c:7316 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7612
 rt_mutex_slowlock_block+0x55e/0x690 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
 full_proxy_write+0x127/0x1f0 fs/debugfs/file.c:388
 vfs_write+0x29f/0xbb0 fs/read_write.c:685
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f086a39e0d9
RSP: 002b:00007f08699fe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f086a625fa0 RCX: 00007f086a39e0d9
RDX: 0000000000000001 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f086a435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f086a626038 R14: 00007f086a625fa0 R15: 00007fff7fc08508
 </TASK>
INFO: task syz.3.5202:16747 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.5202      state:D stack:28464 pid:16747 tgid:16743 ppid:5740   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16df/0x5510 kernel/sched/core.c:7239
 __schedule_loop kernel/sched/core.c:7316 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7612
 rt_mutex_slowlock_block+0x55e/0x690 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
 full_proxy_write+0x127/0x1f0 fs/debugfs/file.c:388
 vfs_write+0x29f/0xbb0 fs/read_write.c:685
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3e11e9e0d9
RSP: 002b:00007f3e114fe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3e12125fa0 RCX: 00007f3e11e9e0d9
RDX: 0000000000000001 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f3e11f35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e12126038 R14: 00007f3e12125fa0 R15: 00007ffdb41d3fc8
 </TASK>
INFO: task syz.1.5203:16748 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.5203      state:D stack:28464 pid:16748 tgid:16746 ppid:14933  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16df/0x5510 kernel/sched/core.c:7239
 __schedule_loop kernel/sched/core.c:7316 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7612
 rt_mutex_slowlock_block+0x55e/0x690 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
 full_proxy_write+0x127/0x1f0 fs/debugfs/file.c:388
 vfs_write+0x29f/0xbb0 fs/read_write.c:685
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1bcc5be0d9
RSP: 002b:00007f1bcbc1e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1bcc845fa0 RCX: 00007f1bcc5be0d9
RDX: 0000000000000001 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f1bcc655024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1bcc846038 R14: 00007f1bcc845fa0 R15: 00007fff2edb8788
 </TASK>

Showing all locks held in the system:
locks held by pr/legacy/17: 4, last CPU#0:
 #0: ffffffff8e1b5640 (console_lock){+.+.}-{0:0}, at: legacy_kthread_func+0x1a3/0x250 kernel/printk/printk.c:3711
 #1: ffffffff8e09cf38 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline]
 #1: ffffffff8e09cf38 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
 #1: ffffffff8e09cf38 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
 #1: ffffffff8e09cf38 (console_srcu){....}-{0:0}, at: console_flush_one_record+0xfa/0xb50 kernel/printk/printk.c:3246
 #2: ffffffff99e3a998 (&port_lock_key){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #2: ffffffff99e3a998 (&port_lock_key){+.+.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:719 [inline]
 #2: ffffffff99e3a998 (&port_lock_key){+.+.}-{3:3}, at: serial8250_console_write+0x17c/0x1b40 drivers/tty/serial/8250/8250_port.c:3344
 #3: ffffffff8e1c3480 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #3: ffffffff8e1c3480 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #3: ffffffff8e1c3480 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #3: ffffffff8e1c3480 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
locks held by khungtaskd/38: 1, last CPU#1:
 #0: ffffffff8e1c3480 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e1c3480 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffffffff8e1c3480 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6793
locks held by getty/5340: 2, on CPU#1:
 #0: ffff8880364f80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/16378: 7, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88803cd28478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
 #4: ffff88801d6b0160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #4: ffff88801d6b0160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
 #4: ffff88801d6b0160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369
 #5: ffff888020e8c310 (&devlink->lock_key#5){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1799
 #6: ffff88805c8063e8 (&sb->s_type->i_mutex_key#8/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1070 [inline]
 #6: ffff88805c8063e8 (&sb->s_type->i_mutex_key#8/2){+.+.}-{4:4}, at: __simple_recursive_removal+0x19a/0x520 fs/libfs.c:619
locks held by syz.2.5200/16744: 3, on CPU#1:
 #0: ffff888033c69f28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #2: ffff888020e8c310 (&devlink->lock_key#5){+.+.}-{4:4}, at: nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
locks held by syz.4.5201/16745: 3, on CPU#1:
 #0: ffff888033c68728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #2: ffff888020e8c310 (&devlink->lock_key#5){+.+.}-{4:4}, at: nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
locks held by syz.3.5202/16747: 3, on CPU#0:
 #0: ffff88803602d728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #2: ffff888020e8c310 (&devlink->lock_key#5){+.+.}-{4:4}, at: nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
locks held by syz.1.5203/16748: 3, on CPU#0:
 #0: ffff888036bb2328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #1: ffff88801d6a8510 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #2: ffff888020e8c310 (&devlink->lock_key#5){+.+.}-{4:4}, at: nsim_bus_dev_max_vfs_write+0x22c/0x3d0 drivers/net/netdevsim/dev.c:276
locks held by syz-executor/16825: 4, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff888029f22878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16829: 4, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88803e406078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16831: 4, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88803e405078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16832: 4, on CPU#0:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88801b779c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16899: 4, on CPU#0:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88802c311478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16926: 4, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff888032229878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16928: 4, on CPU#0:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff888032212c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16932: 4, on CPU#0:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff888036b4e078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/16936: 4, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88803f984478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/17002: 4, on CPU#0:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88803dba5878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/17025: 4, on CPU#0:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff888039e27878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/17026: 4, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff888037ebdc78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/17029: 4, on CPU#1:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88802b57c078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/17030: 4, on CPU#0:
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
 #0: ffff888035442510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88802b57dc78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028d07f08 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee23498 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:65
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 5e f7 6d fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 7f 88 d7 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167a28 EFLAGS: 00000202
RAX: 1ffffffff33c7500 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8557dc20 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99e3a9c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125c32000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562fe7feca38 CR3: 000000000dfb0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:128 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
 wait_for_lsr+0x190/0x300 drivers/tty/serial/8250/8250_port.c:1982
 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3235 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3300 [inline]
 serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3385
 console_emit_next_record kernel/printk/printk.c:3163 [inline]
 console_flush_one_record+0x642/0xb50 kernel/printk/printk.c:3269
 legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>