INFO: task kworker/u8:7:302 blocked in I/O wait for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:7 state:D stack:22696 pid:302 tgid:302 ppid:2 task_flags:0x4248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5583 [inline]
__schedule+0x17dd/0x5830 kernel/sched/core.c:7382
__schedule_loop kernel/sched/core.c:7459 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7474
io_schedule+0x7f/0xd0 kernel/sched/core.c:8146
bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258
__wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52
out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67
wait_on_bit_io include/linux/wait_bit.h:106 [inline]
do_get_write_access+0x658/0x10c0 fs/jbd2/transaction.c:1113
jbd2_journal_get_write_access+0x1d7/0x230 fs/jbd2/transaction.c:1263
__ext4_journal_get_write_access+0xec/0x620 fs/ext4/ext4_jbd2.c:253
ext4_mb_mark_context+0x325/0xec0 fs/ext4/mballoc.c:4123
ext4_mb_mark_diskspace_used+0x338/0x760 fs/ext4/mballoc.c:4239
ext4_mb_new_blocks+0x1062/0x4520 fs/ext4/mballoc.c:6327
ext4_ext_map_blocks+0x1427/0x5480 fs/ext4/extents.c:4469
ext4_map_create_blocks+0x116/0x530 fs/ext4/inode.c:697
ext4_map_blocks+0xe8e/0x1c60 fs/ext4/inode.c:942
mpage_map_one_extent fs/ext4/inode.c:2505 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2601 [inline]
ext4_do_writepages+0x1978/0x44a0 fs/ext4/inode.c:3077
ext4_writepages+0x1fe/0x4e0 fs/ext4/inode.c:3171
do_writepages+0x338/0x560 mm/page-writeback.c:2562
__writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1809
writeback_sb_inodes+0x9de/0x1af0 fs/fs-writeback.c:2120
__writeback_inodes_wb+0x114/0x250 fs/fs-writeback.c:2196
wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2307
wb_check_old_data_flush fs/fs-writeback.c:2411 [inline]
wb_do_writeback fs/fs-writeback.c:2490 [inline]
wb_workfn+0xc92/0x10f0 fs/fs-writeback.c:2518
process_one_work kernel/workqueue.c:3495 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task jbd2/sda1-8:4969 blocked in I/O wait for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8 state:D stack:26280 pid:4969 tgid:4969 ppid:2 task_flags:0x240040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5583 [inline]
__schedule+0x17dd/0x5830 kernel/sched/core.c:7382
__schedule_loop kernel/sched/core.c:7459 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7474
io_schedule+0x7f/0xd0 kernel/sched/core.c:8146
bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258
__wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52
out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67
wait_on_buffer include/linux/buffer_head.h:476 [inline]
jbd2_journal_commit_transaction+0x2f6e/0x5c80 fs/jbd2/commit.c:834
kjournald2+0x3bc/0x740 fs/jbd2/journal.c:200
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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:
locks held by khungtaskd/35: 1, last CPU#1:
#0: ffffffff9015a560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff9015a560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff9015a560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:7/302: 6, on CPU#0:
#0: ffff888021ead148 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888021ead148 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888021ead148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff888021ead148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc9000324fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000324fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000324fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc9000324fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff888037962100 (&type->s_umount_key#34){++++}-{4:4}, at: super_trylock_shared+0x23/0xf0 fs/super.c:642
#3: ffff888037974cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1f1/0x4e0 fs/ext4/inode.c:3170
#4: ffff88803799c950 (jbd2_handle){.+.+}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444
#5: ffff8880356aca98 (&ei->i_data_sem#2){++++}-{4:4}, at: ext4_map_blocks+0xacb/0x1c60 fs/ext4/inode.c:926
locks held by dhcpcd/5300: 1, last CPU#0:
#0: ffffffff90908398 (tomoyo_ss){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:213 [inline]
#0: ffffffff90908398 (tomoyo_ss){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:320 [inline]
#0: ffffffff90908398 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_read_lock security/tomoyo/common.h:1112 [inline]
#0: ffffffff90908398 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_path_number_perm+0x219/0x5f0 security/tomoyo/file.c:727
locks held by getty/5396: 2, on CPU#0:
#0: ffff88803701e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032362e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:377 [inline]
watchdog+0x1073/0x10f0 kernel/hung_task.c:598
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 5301 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:pcpu_next_fit_region+0x0/0x7f0 mm/percpu.c:422
Code: ae ff e8 e3 b7 a9 ff 89 e8 5b 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 70 4d 89 c5 49 89 ce 48 89
RSP: 0018:ffffc9000354f840 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88801deae600 RCX: ffffc9000354f874
RDX: 0000000000000010 RSI: 0000000000000010 RDI: ffff88801deae600
RBP: 0000000000000010 R08: ffffc9000354f870 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520006a9f04 R12: 0000000000009c00
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000008dca
FS: 00007fdf8ab81780(0000) GS:ffff88812336a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c2a71c5000 CR3: 000000007f540000 CR4: 00000000003526f0
Call Trace:
pcpu_find_block_fit+0x174/0x3f0 mm/percpu.c:1124
pcpu_alloc_noprof+0x4d4/0x1900 mm/percpu.c:1826
mm_alloc_cid_noprof include/linux/mm_types.h:1631 [inline]
mm_init+0x87d/0xcb0 kernel/fork.c:1140
dup_mm kernel/fork.c:1544 [inline]
copy_mm+0x29a/0x640 kernel/fork.c:1602
copy_process+0x1ecc/0x4510 kernel/fork.c:2328
kernel_clone+0x2d7/0x940 kernel/fork.c:2798
__do_sys_clone kernel/fork.c:2940 [inline]
__se_sys_clone kernel/fork.c:2924 [inline]
__x64_sys_clone+0x1b6/0x230 kernel/fork.c:2924
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdf8ac55636
Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffdd3553510 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffdd3553518 RCX: 00007fdf8ac55636
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffdd3573a60 R08: 0000000000000000 R09: 0000000000000001
R10: 00007fdf8ab81a50 R11: 0000000000000246 R12: 00007ffdd3553650
R13: 0000000000000000 R14: 0000000000000000 R15: 000055c28f724ac0
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.246 msecs