INFO: task kworker/u8:4:59 blocked for more than 143 seconds.
      Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:22216 pid:59    tgid:59    ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:9)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
 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+0x6f1/0xff0 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+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/0:0/9:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
3 locks held by kworker/u8:2/36:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc90000ac7bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000ac7bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffffffff8f4fd308 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
4 locks held by kworker/u8:4/59:
 #0: ffff88801feda948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801feda948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000210fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000210fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff88805e23c0e0 (&type->s_umount_key#91){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
 #3: ffff88804ca701c8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
2 locks held by getty/5586:
 #0: ffff8880310f60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by kworker/0:3/5813:
4 locks held by syz.9.447/10769:
2 locks held by syz.3.539/11719:
 #0: ffff88805e23c0e0 (&type->s_umount_key#91){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
 #0: ffff88805e23c0e0 (&type->s_umount_key#91){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
 #1: ffff888142f507d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline]
 #1: ffff888142f507d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831
8 locks held by syz-executor/13145:
 #0: ffff888030618428 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3092 [inline]
 #0: ffff888030618428 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682
 #1: ffff888031206088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e0/0x4f0 fs/kernfs/file.c:325
 #2: ffff888143b08b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x203/0x4f0 fs/kernfs/file.c:326
 #3: ffffffff8ed98ec8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:216
 #4: ffff88807b6730e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline]
 #4: ffff88807b6730e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1094 [inline]
 #4: ffff88807b6730e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x7c0 drivers/base/dd.c:1292
 #5: ffff88807b677250 (&devlink->lock_key#9){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1675
 #6: ffffffff8f4fd308 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xdb/0x670 drivers/net/netdevsim/netdev.c:1063
 #7: ffffffff8e144b78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #7: ffffffff8e144b78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #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:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 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: 13389 Comm: kworker/u8:10 Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:unwind_next_frame+0x514/0x2390 arch/x86/kernel/unwind_orc.c:512
Code: e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 63 18 00 00 0f b7 1e c1 eb 0b 80 e3 01 48 8b 44 24 28 0f b6 04 28 84 c0 4c 8b 7c 24 70 <0f> 85 6d 18 00 00 48 8b 44 24 10 88 18 0f b7 1e 83 e3 0f 83 fb 05
RSP: 0018:ffffc9000e2f7438 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8fb47de4
RDX: ffffffff903020de RSI: ffffffff903020e2 RDI: ffffffff8be1af20
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff81728de5
R10: ffffc9000e2f7558 R11: ffffffff81ace580 R12: ffffffff903020e3
R13: ffffc9000e2f7558 R14: ffffc9000e2f7508 R15: ffffc9000e2f7540
FS:  0000000000000000(0000) GS:ffff888125d89000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68f911a7e8 CR3: 000000007924c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 skb_release_data+0x62d/0x7c0 net/core/skbuff.c:1087
 skb_release_all net/core/skbuff.c:1152 [inline]
 __kfree_skb net/core/skbuff.c:1166 [inline]
 consume_skb+0x9e/0xf0 net/core/skbuff.c:1398
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline]
 nsim_dev_trap_report_work+0x7cf/0xb80 drivers/net/netdevsim/dev.c:851
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>