INFO: task kworker/u8:4:78 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:16136 pid:78    tgid:78    ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:5)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 __mutex_lock_common kernel/locking/mutex.c:678 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746
 jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:132
 write_inode fs/fs-writeback.c:1525 [inline]
 __writeback_single_inode+0x6ee/0xff0 fs/fs-writeback.c:1745
 writeback_sb_inodes+0x6b5/0x1000 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
 wb_do_writeback fs/fs-writeback.c:2315 [inline]
 wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
4 locks held by kworker/u8:4/78:
 #0: ffff88801d2e9148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801d2e9148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc900015c7c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc900015c7c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffff8880751e40e0 (&type->s_umount_key#101){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562
 #3: ffff88805a1eb918 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
3 locks held by kworker/u8:8/3459:
 #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc9000c357c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000c357c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffffffff8f2e2588 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
2 locks held by getty/5579:
 #0: ffff88814d1e30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
4 locks held by syz.5.185/7471:
8 locks held by syz-executor/9623:
 #0: ffff88802ecea420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3041 [inline]
 #0: ffff88802ecea420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:680
 #1: ffff888031a00c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e0/0x4f0 fs/kernfs/file.c:325
 #2: ffff888144397e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x203/0x4f0 fs/kernfs/file.c:326
 #3: ffffffff8eb82568 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:216
 #4: ffff88805aaa50e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #4: ffff88805aaa50e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1094 [inline]
 #4: ffff88805aaa50e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x7c0 drivers/base/dd.c:1292
 #5: ffff88805aaa6250 (&devlink->lock_key){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1675
 #6: ffffffff8f2e2588 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xdb/0x670 drivers/net/netdevsim/netdev.c:1059
 #7: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
 #7: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998
2 locks held by syz.4.500/9886:
3 locks held by syz.7.502/9861:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 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: 5809 Comm: syz-executor Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:update_curr+0x78/0x8b0 kernel/sched/fair.c:1237
Code: ec 03 43 80 3c 2c 00 74 08 4c 89 ff e8 71 c7 89 00 48 85 db 0f 84 28 06 00 00 49 8b 3f 48 89 7c 24 18 48 89 de e8 98 75 fd ff <48> 85 c0 0f 8e 0f 06 00 00 48 89 c5 4c 89 64 24 48 49 89 dc 49 c1
RSP: 0018:ffffc9000411f748 EFLAGS: 00000006
RAX: 00000000003dbef9 RBX: ffff8880244b3c80 RCX: b2c712d343ab8500
RDX: 0000000000000009 RSI: ffffffff8d9213f3 RDI: ffffffff8bc0fee0
RBP: ffff8880b8939a80 R08: 0000000000000009 R09: 1ffffffff1efb4ee
R10: dffffc0000000000 R11: fffffbfff1efb4ef R12: 1ffff1101712737f
R13: dffffc0000000000 R14: ffff8880b8939a80 R15: ffff8880b8939bf8
FS:  0000555590c48500(0000) GS:ffff888126200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdad2b3f28 CR3: 0000000033078000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dequeue_entity+0x27/0x1690 kernel/sched/fair.c:5457
 dequeue_entities+0x1fa/0x1510 kernel/sched/fair.c:7089
 dequeue_task_fair+0x2a1/0x690 kernel/sched/fair.c:7188
 block_task kernel/sched/core.c:2145 [inline]
 try_to_block_task kernel/sched/core.c:6602 [inline]
 __schedule+0x5b8/0x4c70 kernel/sched/core.c:6716
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 do_nanosleep+0x1c7/0x600 kernel/time/hrtimer.c:2100
 hrtimer_nanosleep+0x169/0x360 kernel/time/hrtimer.c:2147
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1407 [inline]
 __se_sys_clock_nanosleep+0x2ee/0x380 kernel/time/posix-timers.c:1384
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4b9ddc11e3
Code: 1f 84 00 00 00 00 00 83 ff 03 74 7b 83 ff 02 b8 fa ff ff ff 49 89 ca 0f 44 f8 80 3d 5e 33 1c 00 00 74 14 b8 e6 00 00 00 0f 05 <f7> d8 c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 28 48 89 54 24 10
RSP: 002b:00007ffdc6df6cc8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b9ddc11e3
RDX: 00007ffdc6df6ce0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000018a74446 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffdc6df7130
R13: 0000000000000004 R14: 00007ffdc6df6d1c R15: 00007ffdc6df6db0
 </TASK>