INFO: task kworker/u8:1:13 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:1 state:D stack:23336 pid:13 tgid:13 ppid:2 task_flags:0x4248160 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
io_schedule+0xbf/0x130 kernel/sched/core.c:7871
rq_qos_wait+0x22f/0x340 block/blk-rq-qos.c:307
__wbt_wait block/blk-wbt.c:596 [inline]
wbt_wait+0x1b8/0x3a0 block/blk-wbt.c:656
__rq_qos_throttle+0x56/0xa0 block/blk-rq-qos.c:66
rq_qos_throttle block/blk-rq-qos.h:168 [inline]
rq_qos_throttle block/blk-rq-qos.h:163 [inline]
blk_mq_get_new_requests block/blk-mq.c:3042 [inline]
blk_mq_submit_bio+0x28a1/0x3380 block/blk-mq.c:3193
__submit_bio+0x3cf/0x690 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x53d/0xc10 block/blk-core.c:755
submit_bio_noacct+0x5bd/0x1f60 block/blk-core.c:879
ext4_io_submit fs/ext4/page-io.c:404 [inline]
io_submit_add_bh fs/ext4/page-io.c:445 [inline]
ext4_bio_write_folio+0x756/0x1dc0 fs/ext4/page-io.c:589
mpage_process_page_bufs+0x47c/0x8d0 fs/ext4/inode.c:2191
mpage_prepare_extent_to_map+0x79f/0x14d0 fs/ext4/inode.c:2736
ext4_do_writepages+0xa11/0x3cf0 fs/ext4/inode.c:2877
ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3025
do_writepages+0x27a/0x600 mm/page-writeback.c:2604
__writeback_single_inode+0x160/0xfb0 fs/fs-writeback.c:1719
writeback_sb_inodes+0x60d/0xfa0 fs/fs-writeback.c:2015
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2086
wb_writeback+0x7f3/0xb70 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+0x8ca/0xbe0 fs/fs-writeback.c:2382
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task syz.0.188:6785 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.188 state:D stack:28680 pid:6785 tgid:6785 ppid:6311 task_flags:0x440040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
io_schedule+0xbf/0x130 kernel/sched/core.c:7871
bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:250
__wait_on_bit+0x65/0x180 kernel/sched/wait_bit.c:52
out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:67
wait_on_bit_io include/linux/wait_bit.h:105 [inline]
do_get_write_access+0x93d/0x1320 fs/jbd2/transaction.c:1092
jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1241
__ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:242
ext4_reserve_inode_write+0x1be/0x340 fs/ext4/inode.c:6305
__ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6480
ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6517
__mark_inode_dirty+0x1ee/0xe40 fs/fs-writeback.c:2566
generic_update_time+0xcf/0xf0 fs/inode.c:2117
inode_update_time fs/inode.c:2130 [inline]
__file_update_time fs/inode.c:2357 [inline]
file_update_time+0x17d/0x1c0 fs/inode.c:2387
ext4_page_mkwrite+0x33d/0x1880 fs/ext4/inode.c:6683
do_page_mkwrite+0x174/0x380 mm/memory.c:3489
do_shared_fault mm/memory.c:5792 [inline]
do_fault mm/memory.c:5854 [inline]
do_pte_missing+0x29d/0x3ba0 mm/memory.c:4362
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x1556/0x2aa0 mm/memory.c:6336
handle_mm_fault+0x589/0xd10 mm/memory.c:6505
do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7efec386547b
RSP: 002b:00007fff15257e30 EFLAGS: 00010246
RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b2e120000 RSI: 0000000000040000 RDI: 00007efec3a98d50
RBP: 0000000000000000 R08: 0000000000000009 R09: 00007fff15257b75
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000023d3c R15: 00007fff152580e0
Showing all locks held in the system:
4 locks held by kworker/u8:1/13:
#0: ffff88801e6ad148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc90000127d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffff88814e51c0e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562
#3: ffff88814e51eb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x27a/0x600 mm/page-writeback.c:2604
1 lock held by khungtaskd/31:
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5589:
#0: ffff88814d7730a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
3 locks held by syz.0.188/6785:
#0: ffff88805906ba88 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x117/0x530 mm/mmap_lock.c:238
#1: ffff88814e51c518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x174/0x380 mm/memory.c:3489
#2: ffff88814e520950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
3 locks held by syz-executor/6786:
#0: ffff88814e51c420 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10e/0x4a0 fs/namei.c:4219
#1: ffff8880765b6380 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1025 [inline]
#1: ffff8880765b6380 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1bb/0x4a0 fs/namei.c:4226
#2: ffff88814e520950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
=============================================
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 10/25/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x8/0x20 kernel/kcov.c:320
Code: 00 00 00 e9 2a fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 0c 24 <48> 89 f2 48 89 fe bf 07 00 00 00 e9 f8 fd ff ff 0f 1f 84 00 00 00
RSP: 0018:ffffffff8e007d30 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff8880b84285e0 RCX: ffffffff81ad654a
RDX: 1ffff110170850c8 RSI: 00000044057f3980 RDI: 7fffffffffffffff
RBP: 1ffffffff1c00faf R08: 0000000000000006 R09: 0000004c3ebba780
R10: 00000044057f3980 R11: 0000000000000001 R12: 00000044057f3980
R13: 7fffffffffffffff R14: 00000044057f3980 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124a0d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d8f218d460 CR3: 000000000e182000 CR4: 00000000003526f0
Call Trace:
tick_nohz_stop_tick kernel/time/tick-sched.c:1055 [inline]
tick_nohz_idle_stop_tick+0x65a/0xef0 kernel/time/tick-sched.c:1227
cpuidle_idle_call kernel/sched/idle.c:188 [inline]
do_idle+0x388/0x500 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
rest_init+0x16b/0x2b0 init/main.c:757
start_kernel+0x3f6/0x4e0 init/main.c:1111
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148