INFO: task kworker/u4:5:1109 blocked for more than 143 seconds.
Not tainted 6.6.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5 state:D stack:13264 pid:1109 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x405/0x1460 kernel/sched/core.c:6695
schedule+0x59/0xa0 kernel/sched/core.c:6771
schedule_preempt_disabled+0x1b/0xa0 kernel/sched/core.c:6830
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x53b/0x9e0 kernel/locking/mutex.c:747
fat_write_inode fs/fat/inode.c:910 [inline]
fat_write_inode+0x37/0x60 fs/fat/inode.c:903
write_inode fs/fs-writeback.c:1456 [inline]
__writeback_single_inode+0x30d/0x3e0 fs/fs-writeback.c:1673
writeback_sb_inodes+0x1fb/0x500 fs/fs-writeback.c:1899
__writeback_inodes_wb+0x47/0xe0 fs/fs-writeback.c:1970
wb_writeback+0x2b4/0x350 fs/fs-writeback.c:2077
wb_check_background_flush fs/fs-writeback.c:2147 [inline]
wb_do_writeback fs/fs-writeback.c:2235 [inline]
wb_workfn+0x2f1/0x550 fs/fs-writeback.c:2262
process_one_work+0x208/0x4c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x1c3/0x380 kernel/workqueue.c:2784
kthread+0xde/0x110 kernel/kthread.c:388
ret_from_fork+0x2c/0x40 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
Showing all locks held in the system:
1 lock held by khungtaskd/28:
#0: ffffffff831794c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline]
#0: ffffffff831794c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline]
#0: ffffffff831794c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x36/0x120 kernel/locking/lockdep.c:6613
4 locks held by kworker/u4:5/1109:
#0: ffff888140e7cd38 ((wq_completion)writeback){....}-{0:0}, at: process_one_work+0x1a2/0x4c0 kernel/workqueue.c:2605
#1: ffffc90002a9fe50 ((work_completion)(&(&wb->dwork)->work)){....}-{0:0}, at: process_one_work+0x1a2/0x4c0 kernel/workqueue.c:2605
#2: ffff8881026910e0 (&type->s_umount_key#47){....}-{3:3}, at: super_trylock_shared+0x15/0x50 fs/super.c:610
#3: ffff88810e14a1d0 (&sbi->s_lock){....}-{3:3}, at: fat_write_inode fs/fat/inode.c:910 [inline]
#3: ffff88810e14a1d0 (&sbi->s_lock){....}-{3:3}, at: fat_write_inode+0x37/0x60 fs/fat/inode.c:903
2 locks held by getty/1672:
#0: ffff888102ac20a0 (&tty->ldisc_sem){....}-{0:0}, at: tty_ldisc_ref_wait+0x23/0x50 drivers/tty/tty_ldisc.c:243
#1: ffffc900011fb2f0 (&ldata->atomic_read_lock){....}-{3:3}, at: n_tty_read+0x519/0x650 drivers/tty/n_tty.c:2206
4 locks held by syz-executor.0/2655:
1 lock held by syz-executor.0/1403:
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.6.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x3d/0x60 lib/dump_stack.c:106
nmi_cpu_backtrace+0xcc/0x110 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0xd1/0x130 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0x615/0x640 kernel/hung_task.c:379
kthread+0xde/0x110 kernel/kthread.c:388
ret_from_fork+0x2c/0x40 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted 6.6.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:__lock_acquire.constprop.0+0x490/0x540 kernel/locking/lockdep.c:5132
Code: ff 0f b7 c9 39 4c 24 58 0f 8e 1f fe ff ff e8 b7 a2 6a 00 31 c0 eb 87 0f b7 45 f8 66 25 ff 1f 0f b7 c0 48 0f a3 05 10 00 c2 02 <0f> 82 3a fd ff ff 8b 15 9c 49 5e 03 85 d2 0f 85 2c fd ff ff e8 87
RSP: 0018:ffffc900000cbc08 EFLAGS: 00000003
RAX: 00000000000000c1 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888101e4c1d0 R08: 0000000000080001 R09: ffff888101e4c1a8
R10: 0000000000080000 R11: 0000000000000001 R12: 0000000000080001
R13: 0000000000000000 R14: ffff888101e4b780 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4245c1f000 CR3: 0000000003047000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire kernel/locking/lockdep.c:5753 [inline]
lock_acquire+0xab/0x180 kernel/locking/lockdep.c:5718
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x32/0x50 kernel/locking/spinlock.c:162
__debug_check_no_obj_freed lib/debugobjects.c:1020 [inline]
debug_check_no_obj_freed+0xb0/0x250 lib/debugobjects.c:1063
slab_free_hook mm/slub.c:1775 [inline]
slab_free_freelist_hook.constprop.0+0xf4/0x180 mm/slub.c:1826
slab_free mm/slub.c:3809 [inline]
kmem_cache_free+0xde/0x460 mm/slub.c:3831
rcu_do_batch kernel/rcu/tree.c:2139 [inline]
rcu_core+0x4f2/0x750 kernel/rcu/tree.c:2403
__do_softirq+0x12e/0x309 kernel/softirq.c:553
run_ksoftirqd kernel/softirq.c:921 [inline]
run_ksoftirqd+0x25/0x30 kernel/softirq.c:913
smpboot_thread_fn+0x175/0x210 kernel/smpboot.c:164
kthread+0xde/0x110 kernel/kthread.c:388
ret_from_fork+0x2c/0x40 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304