INFO: task kworker/u8:14:1522 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/u8:14 state:D stack:21856 pid:1522 tgid:1522 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:9)
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7282
io_schedule+0x80/0xe0 kernel/sched/core.c:8109
TXN_SLEEP_DROP_LOCK fs/jfs/jfs_txnmgr.c:125 [inline]
txBegin+0x27d/0xc00 fs/jfs/jfs_txnmgr.c:376
jfs_commit_inode+0x1b3/0x530 fs/jfs/inode.c:107
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x75d/0x10e0 fs/fs-writeback.c:1825
writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2054
wb_writeback+0x445/0xb00 fs/fs-writeback.c:2239
wb_do_writeback fs/fs-writeback.c:2386 [inline]
wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2426
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 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 syz-executor:6835 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:22040 pid:6835 tgid:6835 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7282
wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227
__writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2845
sync_filesystem+0xa2/0x250 fs/sync.c:54
generic_shutdown_super+0x77/0x2d0 fs/super.c:625
kill_block_super+0x44/0x90 fs/super.c:1725
deactivate_locked_super+0xbc/0x130 fs/super.c:476
cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcd2761da57
RSP: 002b:00007fff1f2df118 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fcd276b2048 RCX: 00007fcd2761da57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff1f2df1d0
RBP: 00007fff1f2df1d0 R08: 00007fff1f2e01d0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff1f2e0260
R13: 00007fcd276b2048 R14: 0000000000044a39 R15: 00007fff1f2e02a0
Showing all locks held in the system:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/37:
#0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:7/194:
#0: ffff88801a08c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801a08c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc90003c37c40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc90003c37c40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
2 locks held by kworker/u8:14/1522:
#0: ffff88801f6ef938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801f6ef938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc90006ebfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc90006ebfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
2 locks held by getty/5571:
#0: ffff88803734e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/6835:
#0: ffff8880288460d0 (&type->s_umount_key#78){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880288460d0 (&type->s_umount_key#78){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880288460d0 (&type->s_umount_key#78){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
1 lock held by syz-executor/7133:
#0: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3216 [inline]
#0: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3408 [inline]
#0: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xcab/0x2840 mm/page_alloc.c:3943
10 locks held by syz-executor/7518:
3 locks held by udevd/7548:
#0: ffff888038038480 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#0: ffff888038038480 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff8880608d7390 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#1: ffff8880608d7390 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: shmem_file_write_iter+0x82/0x120 mm/shmem.c:3468
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3216 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3408 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xcab/0x2840 mm/page_alloc.c:3943
3 locks held by udevd/7929:
#0: ffff888022b87348 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1044 [inline]
#0: ffff888022b87348 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:854
#1: ffff88803188aab0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline]
#1: ffff88803188aab0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
#1: ffff88803188aab0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3216 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3408 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xcab/0x2840 mm/page_alloc.c:3943
3 locks held by udevd/7955:
#0: ffff888038038480 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#0: ffff888038038480 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff88803cccce38 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#1: ffff88803cccce38 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: shmem_file_write_iter+0x82/0x120 mm/shmem.c:3468
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3216 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3408 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xcab/0x2840 mm/page_alloc.c:3943
3 locks held by udevd/8230:
2 locks held by kworker/u8:12/8870:
#0: ffff88801a08c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801a08c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc900045ffc40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc900045ffc40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
1 lock held by syz.7.416/9115:
3 locks held by syz.0.415/9122:
#0: ffff88801b2b2480 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#0: ffff88801b2b2480 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff888064508388 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#1: ffff888064508388 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: shmem_file_write_iter+0x82/0x120 mm/shmem.c:3468
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3216 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3408 [inline]
#2: ffff88813fffc358 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xcab/0x2840 mm/page_alloc.c:3943
5 locks held by syz.4.417/9137:
7 locks held by dhcpcd-run-hook/9139:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [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:353 [inline]
watchdog+0xfd3/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 8e bc 90 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 1f c6 f7 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 5a 9e fc 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff3372a00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99b957f0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8533d980 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b95560 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881261fb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f47c60e56b8 CR3: 000000005f0a2000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline]
serial8250_console_write+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3357
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
kthread+0x388/0x470 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