INFO: task kworker/u4:14:4693 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:14 state:D stack:23120 pid:4693 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:9)
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x562/0xaf0 kernel/locking/mutex.c:747
jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:108
jfs_write_inode+0x141/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1470 [inline]
__writeback_single_inode+0x75b/0x1160 fs/fs-writeback.c:1687
writeback_sb_inodes+0xb30/0x1850 fs/fs-writeback.c:1913
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:1984
wb_writeback+0x494/0xd50 fs/fs-writeback.c:2089
wb_check_background_flush fs/fs-writeback.c:2155 [inline]
wb_do_writeback fs/fs-writeback.c:2243 [inline]
wb_workfn+0xc1c/0xee0 fs/fs-writeback.c:2270
process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2df30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2e750 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
#0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4023:
#0: ffff88802f597098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198
5 locks held by kworker/u4:5/4295:
#0: ffff888017616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#1: ffffc900043c7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd39fd0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
#3: ffff888055deb2f8 (&devlink->lock_key#15){+.+.}-{3:3}, at: devlink_pernet_pre_exit+0x104/0x280 net/devlink/leftover.c:12502
#4: ffffffff8cb33140 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023
4 locks held by kworker/u4:14/4693:
#0: ffff8880186f9938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#1: ffffc900036f7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#2: ffff88807af700e0 (&type->s_umount_key#55){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:415
#3: ffff888050f0b008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:108
4 locks held by syz.9.407/6640:
1 lock held by syz-executor/6667:
#0: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#0: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
2 locks held by kworker/0:14/6794:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#1: ffffc900039ffd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
1 lock held by syz.0.900/9367:
#0: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#0: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
2 locks held by sed/9402:
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9390 Comm: syz.2.902 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:__lock_acquire+0x20f/0x7d10 kernel/locking/lockdep.c:4957
Code: 8b 6d 20 48 c7 c0 00 f1 47 90 49 29 c7 49 c1 ff 06 48 ba ab aa aa aa aa aa aa aa 49 0f af d7 41 89 d7 48 8b 44 24 60 48 85 c0 <4c> 89 a4 24 88 00 00 00 0f 84 3d 01 00 00 4d 8d b4 24 e0 0a 00 00
RSP: 0018:ffffc900033571a0 EFLAGS: 00000002
RAX: 0000000000000002 RBX: ffff88813fffa7c8 RCX: ffffffff96bfe103
RDX: 0000000000000023 RSI: 0000000000000000 RDI: ffff88813fffa7c8
RBP: ffffc900033573f0 R08: dffffc0000000000 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff1c3fbde R12: ffff8880af071dc0
R13: 0000000000000000 R14: ffff8880af072898 R15: 0000000000000023
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555d92152950 CR3: 00000000645f9000 CR4: 00000000003506f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
seqcount_lockdep_reader_access+0xb8/0x190 include/linux/seqlock.h:102
read_seqbegin include/linux/seqlock.h:893 [inline]
zone_span_seqbegin include/linux/memory_hotplug.h:132 [inline]
page_outside_zone_boundaries mm/page_alloc.c:654 [inline]
bad_range+0x7a/0x2d0 mm/page_alloc.c:681
__free_one_page+0x133/0xc60 mm/page_alloc.c:1141
free_pcppages_bulk+0x33e/0x690 mm/page_alloc.c:1636
free_unref_page+0x18d/0x3f0 mm/page_alloc.c:3531
__vunmap+0x856/0xa00 mm/vmalloc.c:2726
kcov_put kernel/kcov.c:437 [inline]
kcov_close+0x27/0x50 kernel/kcov.c:533
__fput+0x22c/0x920 fs/file_table.c:320
task_work_run+0x1d0/0x260 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0x982/0x2480 kernel/exit.c:880
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
get_signal+0x1272/0x1350 kernel/signal.c:2871
arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f126ef9c819
Code: Unable to access opcode bytes at 0x7f126ef9c7ef.
RSP: 002b:00007f126fd75028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f126f216360 RCX: 00007f126ef9c819
RDX: 0000200000002280 RSI: 0000000000008914 RDI: 0000000000000008
RBP: 00007f126f032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f126f2163f8 R14: 00007f126f216360 R15: 00007ffcfbe20c18