INFO: task kworker/u8:34:11948 blocked for more than 143 seconds.
Not tainted 6.15.0-next-20250530-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:34 state:D
stack:21160 pid:11948 tgid:11948 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6878
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
__down_write_common kernel/locking/rwsem.c:1304 [inline]
__down_write kernel/locking/rwsem.c:1313 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578
f2fs_down_write fs/f2fs/f2fs.h:2229 [inline]
f2fs_balance_fs+0x558/0x750 fs/f2fs/segment.c:463
f2fs_write_inode+0x3fb/0x5f0 fs/f2fs/inode.c:819
write_inode fs/fs-writeback.c:1525 [inline]
__writeback_single_inode+0x6ee/0xff0 fs/fs-writeback.c:1745
writeback_sb_inodes+0x6b5/0x1000 fs/fs-writeback.c:1976
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
2 locks held by ksoftirqd/1/23:
1 lock held by khungtaskd/31:
#0: ffffffff8e13f140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13f140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e13f140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by getty/5598:
#0: ffff8880334e80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
4 locks held by kworker/u8:34/11948:
#0: ffff88801eafb948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
#0: ffff88801eafb948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
#1: ffffc900049d7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
#1: ffffc900049d7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
#2: ffff88807e7e20e0 (&type->s_umount_key#58){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88807a4ad410 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2229 [inline]
#3: ffff88807a4ad410 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x558/0x750 fs/f2fs/segment.c:463
5 locks held by syz.4.2075/16609:
1 lock held by udevd/18283:
2 locks held by syz.6.2562/18912:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
watchdog+0xfee/0x1030 kernel/hung_task.c:470
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
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: 18912 Comm: syz.6.2562 Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:task_wait_context kernel/locking/lockdep.c:4793 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4878 [inline]
RIP: 0010:__lock_acquire+0x5a6/0xd20 kernel/locking/lockdep.c:5190
Code: c6 00 00 00 02 0f 84 51 ff ff ff 89 d0 e9 4a ff ff ff 48 c7 c7 70 01 01 8e 48 89 de e8 63 67 58 03 48 8b 3c 24 e9 56 ff ff ff <83> bf d4 0a 00 00 00 41 0f 94 c4 45 00 e4 41 80 c4 03 44 3b bf e8
RSP: 0018:ffffc900046d75a8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000ffffffff
RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffff88802613bc00
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84aabc4d
R10: dffffc0000000000 R11: fffff940003bf49f R12: ffffffffffffffff
R13: 0000000000000001 R14: ffff88802613c740 R15: 0000000000000000
FS: 00007fc89866e6c0(0000) GS:ffff888125d53000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc88dfff000 CR3: 0000000059452000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
blk_cgroup_congested+0x39/0x210 block/blk-cgroup.c:2255
__folio_throttle_swaprate+0x80/0x1c0 mm/swapfile.c:3913
folio_throttle_swaprate include/linux/swap.h:636 [inline]
shmem_add_to_page_cache+0x72c/0xb10 mm/shmem.c:898
shmem_alloc_and_add_folio+0x846/0xf60 mm/shmem.c:1916
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2532
shmem_get_folio mm/shmem.c:2638 [inline]
shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3288
generic_perform_write+0x2c7/0x910 mm/filemap.c:4112
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3463
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x54b/0xa90 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc89778d41f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007fc89866ddf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fc89778d41f
RDX: 0000000001000000 RSI: 00007fc88d000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000050ed
R10: 000020000000a2c2 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fc89866def0 R14: 00007fc89866deb0 R15: 00007fc88d000000