INFO: task kworker/u8:9:1004 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:9 state:D stack:20032 pid:1004 tgid:1004 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:1)
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x16ec/0x5620 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1662 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1739 [inline]
__rt_mutex_slowlock_locked+0x1f28/0x2550 kernel/locking/rtmutex.c:1779
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1819
__rt_mutex_lock kernel/locking/rtmutex.c:1834 [inline]
rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:245
f2fs_down_write fs/f2fs/f2fs.h:2411 [inline]
f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2095
f2fs_balance_fs_bg+0x574/0x9d0 fs/f2fs/segment.c:545
f2fs_write_node_pages+0x158/0x700 fs/f2fs/node.c:2257
do_writepages+0x32e/0x550 mm/page-writeback.c:2571
__writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1764
writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2132
wb_writeback+0x459/0xb00 fs/fs-writeback.c:2243
wb_check_old_data_flush fs/fs-writeback.c:2347 [inline]
wb_do_writeback fs/fs-writeback.c:2400 [inline]
wb_workfn+0xb17/0xf20 fs/fs-writeback.c:2428
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
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
Showing all locks held in the system:
1 lock held by khungtaskd/39:
#0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:9/1004:
#0: ffff88801fab6938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801fab6938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc90005d8fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc90005d8fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffff888063adc0d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
#3: ffff88806bd71a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2411 [inline]
#3: ffff88806bd71a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
#3: ffff88806bd71a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2095
2 locks held by getty/5355:
#0: ffff888036abc0a0 (&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 udevd/5601:
#0: ffff888037356480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
1 lock held by syz-executor/5605:
#0: ffff888034ed2480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
3 locks held by udevd/5619:
1 lock held by udevd/5623:
#0: ffff888037356480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
1 lock held by udevd/5626:
#0: ffff88802285d8c8 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1044 [inline]
#0: ffff88802285d8c8 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:854
7 locks held by kworker/u8:13/6265:
7 locks held by syz.1.131/7091:
1 lock held by syz-executor/8197:
#0: ffff8880398ae480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
3 locks held by syz.8.397/9317:
#0: ffff8880340ecf28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1261
#1: ffff88803a840480 (sb_writers#18){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#1: ffff88803a840480 (sb_writers#18){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#2: ffff888060dc9080 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#2: ffff888060dc9080 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: btrfs_inode_lock+0x51/0xe0 fs/btrfs/inode.c:368
2 locks held by syz.8.397/9359:
#0: ffff88803a840480 (sb_writers#18){.+.+}-{0:0}, at: mnt_want_write_file+0x63/0x210 fs/namespace.c:537
#1: ffff888060dc9080 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#1: ffff888060dc9080 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: btrfs_inode_lock+0x51/0xe0 fs/btrfs/inode.c:368
1 lock held by syz.8.397/9360:
#0: ffff888060dc9080 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1044 [inline]
#0: ffff888060dc9080 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: btrfs_inode_lock+0x65/0xe0 fs/btrfs/inode.c:360
7 locks held by syz.8.397/9361:
6 locks held by syz.6.399/9320:
5 locks held by syz.9.402/9363:
#0: ffff88801db25d08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:310
#1: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#2: ffff88805525c7d8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88805525c7d8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
#3: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#4: ffff8880b8933f68 ((lock)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#4: ffff8880b8933f68 ((lock)#2){+.+.}-{3:3}, at: __folio_batch_add_and_move+0x283/0xa90 mm/swap.c:-1
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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: 26 Comm: irq_work/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:select_task_rq kernel/sched/core.c:3579 [inline]
RIP: 0010:try_to_wake_up+0x4a1/0x1380 kernel/sched/core.c:4290
Code: 00 00 00 e9 3e 03 00 00 b3 01 e9 1a 03 00 00 41 bd 08 00 00 00 eb 5d 4c 8d b5 08 03 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 f7 e8 05 65 97 00 4d 8b 36 49 83 c6 50 4c 89 f0 48 c1
RSP: 0018:ffffc90000a0fbd8 EFLAGS: 00000046
RAX: 1ffff11003a53be9 RBX: 1ffff11003a53b95 RCX: 0000000080000002
RDX: 0000000000000000 RSI: ffffffff8d85fb7f RDI: ffffffff8ba75be0
RBP: ffff88801d29dc40 R08: ffffffff8f886df7 R09: 1ffffffff1f10dbe
R10: dffffc0000000000 R11: fffffbfff1f10dbf R12: dffffc0000000000
R13: 1ffff11003a53b8b R14: ffff88801d29df48 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888126287000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ca71ae000 CR3: 00000000350ec000 CR4: 00000000003526f0
Call Trace:
autoremove_wake_function+0x17/0x100 kernel/sched/wait.c:403
__wake_up_common kernel/sched/wait.c:108 [inline]
__wake_up_common_lock+0x136/0x1e0 kernel/sched/wait.c:125
wake_up_klogd_work_func+0x87/0x120 kernel/printk/printk.c:4604
irq_work_single+0xe9/0x2b0 kernel/irq_work.c:221
irq_work_run_list kernel/irq_work.c:252 [inline]
run_irq_workd+0x173/0x240 kernel/irq_work.c:312
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
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