INFO: task kworker/u8:5:1088 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5 state:D stack:20768 pid:1088 tgid:1088 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:2)
Call Trace:
context_switch kernel/sched/core.c:5254 [inline]
__schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
__schedule_loop kernel/sched/core.c:6944 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6959
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016
rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
f2fs_down_write fs/f2fs/f2fs.h:2294 [inline]
f2fs_balance_fs+0x5ab/0x7f0 fs/f2fs/segment.c:464
f2fs_write_inode+0x3fb/0x5f0 fs/f2fs/inode.c:820
write_inode fs/fs-writeback.c:1564 [inline]
__writeback_single_inode+0x6f1/0xff0 fs/fs-writeback.c:1784
writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:2015
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2086
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2197
wb_check_old_data_flush fs/fs-writeback.c:2301 [inline]
wb_do_writeback fs/fs-writeback.c:2354 [inline]
wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2382
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
4 locks held by kworker/0:1/10:
#0: ffff88801d6ead48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88801d6ead48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc900000f7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc900000f7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff888028446198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff888028446198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4b50 drivers/usb/core/hub.c:5899
#3: ffff8880b863a018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646
1 lock held by khungtaskd/31:
#0: ffffffff8df3d5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df3d5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8df3d5a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:2/36:
4 locks held by kworker/u8:5/1088:
#0: ffff888140e85148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888140e85148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc90003f0fba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc90003f0fba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff888059f540e0 (&type->s_umount_key#78){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562
#3: ffff8880625bd478 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2294 [inline]
#3: ffff8880625bd478 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5ab/0x7f0 fs/f2fs/segment.c:464
3 locks held by kworker/u8:6/1148:
#0: ffff88813fe29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88813fe29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000406fba0 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000406fba0 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffffffff8df43038 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#2: ffffffff8df43038 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957
1 lock held by klogd/5187:
#0: ffff8880b863a018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646
2 locks held by getty/5586:
#0: ffff88814e0be0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
6 locks held by syz.2.3039/20448:
1 lock held by syz.5.3562/22612:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:337 [inline]
watchdog+0xfa9/0xff0 kernel/hung_task.c:500
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 22612 Comm: syz.5.3562 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:deref_stack_reg+0x1c2/0x230 arch/x86/kernel/unwind_orc.c:406
Code: 89 f7 e8 11 08 00 00 49 89 c6 48 8b 5c 24 18 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 83 93 b2 00 4c 89 33 b0 01 02 31 c0 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d e9 47 8f d8
RSP: 0018:ffffc9000d415f20 EFLAGS: 00000246
RAX: 1ffff92001a82c01 RBX: ffffc9000d416088 RCX: 0000000000000001
RDX: ffffc9000d416088 RSI: dffffc0000000000 RDI: ffffc9000d416cf0
RBP: 1ffff92001a82c09 R08: ffffc9000d416cf0 R09: 0000000000000000
R10: ffffc9000d416098 R11: fffff52001a82c15 R12: 1ffff92001a82c0a
R13: 1ffff92001a82c0b R14: ffffc9000d416e90 R15: dffffc0000000000
FS: 00007f328db796c0(0000) GS:ffff888125f22000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f36143b3ad8 CR3: 000000003433e000 CR4: 00000000003526f0
Call Trace:
unwind_next_frame+0x17c4/0x2390 arch/x86/kernel/unwind_orc.c:-1
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:165
__set_page_owner+0x8d/0x4c0 mm/page_owner.c:341
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
prep_new_page mm/page_alloc.c:1859 [inline]
get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3920
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5214
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2418
folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2437
shmem_alloc_folio mm/shmem.c:1871 [inline]
shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1911
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2534
shmem_get_folio mm/shmem.c:2640 [inline]
shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3289
generic_perform_write+0x2c5/0x900 mm/filemap.c:4255
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3464
__kernel_write_iter+0x428/0x910 fs/read_write.c:619
dump_emit_page fs/coredump.c:1298 [inline]
dump_user_range+0x8a0/0xc90 fs/coredump.c:1372
elf_core_dump+0x3369/0x3960 fs/binfmt_elf.c:2111
coredump_write+0x116c/0x1900 fs/coredump.c:1049
vfs_coredump+0x1db5/0x2a60 fs/coredump.c:1170
get_signal+0x1108/0x1340 kernel/signal.c:3019
arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:40 [inline]
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
irqentry_exit_to_user_mode+0x7e/0x110 kernel/entry/common.c:73
exc_general_protection+0x171/0x200 arch/x86/kernel/traps.c:792
asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:612
RIP: 0033:0x7f328cd8efd1
Code: 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 48 3d 01 f0 ff ff 73 01 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:00002000000002a0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f328cfe5fa0 RCX: 00007f328cd8efc9
RDX: 00002000000002c0 RSI: 00002000000002a0 RDI: 000000008c000000
RBP: 00007f328ce11f91 R08: 0000200000000340 R09: 0000200000000340
R10: 0000200000000300 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f328cfe6038 R14: 00007f328cfe5fa0 R15: 00007ffe677ca7f8