INFO: task kworker/u8:8:6004 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:8 state:D stack:20896 pid:6004 tgid:6004 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
netfs_wait_for_in_progress_stream+0x260/0x4b0 fs/netfs/misc.c:370
netfs_retry_writes+0xf9/0x1680 fs/netfs/write_retry.c:214
netfs_collect_write_results fs/netfs/write_collect.c:349 [inline]
netfs_write_collection+0x1ed6/0x2b60 fs/netfs/write_collect.c:365
netfs_write_collection_worker+0x5b/0xa0 fs/netfs/write_collect.c:448
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:5/1326:
#0: ffff8881432c8948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432c8948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000444fbc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000444fbc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
1 lock held by udevd/5228:
2 locks held by getty/5621:
#0: ffff88803388d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by kworker/u8:8/6004:
#0: ffff88801a481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801a481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90005327bc0 ((work_completion)(&rreq->work)#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90005327bc0 ((work_completion)(&rreq->work)#2){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
1 lock held by udevd/6466:
1 lock held by syz.8.1414/12189:
#0: ffff8880579f8b70 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559
1 lock held by syz.9.1610/13303:
1 lock held by syz.3.1612/13322:
2 locks held by cmp/13324:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
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:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 13325 Comm: rm Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:blkcg_maybe_throttle_current+0x4b0/0xb40 block/blk-cgroup.c:2043
Code: 00 48 c7 c2 80 9f e1 8b e8 dd 33 ec fc 48 c7 c7 20 9f 13 8e 4c 89 e6 e8 be 19 ec fc e8 49 c5 f5 fc 48 c7 44 24 60 0e 36 e0 45 <48> b8 00 00 00 00 00 fc ff df 48 8b 4c 24 58 48 c7 04 01 00 00 00
RSP: 0018:ffffc90004e57da0 EFLAGS: 00000293
RAX: ffffffff84b151ab RBX: 0000000000000000 RCX: ffff88801f7f9e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90004e57ec0 R08: ffffffff8fa39f37 R09: 1ffffffff1f473e6
R10: dffffc0000000000 R11: fffffbfff1f473e7 R12: 1ffff11003eff472
R13: 0000000000000000 R14: ffff88801f7fb460 R15: 1ffff11003eff68c
FS: 00007f4ebf99fc80(0000) GS:ffff888125d15000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4ebfa3d1d4 CR3: 000000005a874000 CR4: 0000000000350ef0
Call Trace:
resume_user_mode_work include/linux/resume_user_mode.h:60 [inline]
exit_to_user_mode_loop+0xae/0x110 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4ebfb5d487
Code: 1f 40 00 48 89 f2 31 c9 48 89 fe bf 9c ff ff ff e9 8e c6 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 89 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 41 b9 0d 00 f7 d8 64 89 02 b8
RSP: 002b:00007ffe9f8c4fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000089
RAX: fffffffffffffffe RBX: 00007f4ebfa342fe RCX: 00007f4ebfb5d487
RDX: 00007f4ebfa3d1d4 RSI: 00007ffe9f8c5070 RDI: 00007f4ebfa342fe
RBP: 00007ffe9f8c5070 R08: 00007f4ebfd47af8 R09: 0000000000000000
R10: 00007ffe9f8c4e20 R11: 0000000000000246 R12: 00007ffe9f8c51f8
R13: 00007ffe9f8c5218 R14: 00007f4ebfa3b4d0 R15: 0000000000000000