INFO: task syz.4.1156:11418 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1156 state:D stack:26640 pid:11418 tgid:11417 ppid:7387 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5254 [inline]
__schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
__schedule_loop kernel/sched/core.c:6944 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6959
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
sync_bdevs+0x1ac/0x340 block/bdev.c:1288
ksys_sync+0xb9/0x150 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fab7c58efc9
RSP: 002b:00007fab7d4e4038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fab7c7e5fa0 RCX: 00007fab7c58efc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fab7c7e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fab7c7e6038 R14: 00007fab7c7e5fa0 R15: 00007fff2d362928
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e13d720 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13d720 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e13d720 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5586:
#0: ffff88803379b0a0 (&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
1 lock held by udevd/5847:
#0: ffff88802520f358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
1 lock held by syz.4.1156/11418:
#0: ffff88802520f358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by poweroff/11639:
#0: ffff88802520f358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
2 locks held by syz.6.1589/13163:
1 lock held by syz.0.1590/13165:
1 lock held by syz.0.1590/13183:
#0: ffffffff8e1431b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e1431b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
1 lock held by syz.3.1593/13172:
#0: ffffffff8e1431b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#0: ffffffff8e1431b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957
1 lock held by syz.2.1594/13181:
#0: ffffffff8e143080 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3820
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:337 [inline]
watchdog+0xfa9/0xff0 kernel/hung_task.c:500
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 6107 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: writeback wb_workfn (flush-7:3)
RIP: 0010:match_held_lock+0x2/0xc0 kernel/locking/lockdep.c:5305
Code: 41 5f e9 c1 dd 02 00 cc e8 fb f8 ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 56 <53> bb 01 00 00 00 48 39 77 10 74 6a 81 7f 20 00 00 20 00 72 5f 48
RSP: 0018:ffffc90000007b98 EFLAGS: 00000097
RAX: 0000000000000000 RBX: ffff888025b62970 RCX: a7ae674efcd00d00
RDX: 0000000000000008 RSI: ffff8880308c46e8 RDI: ffff888025b62970
RBP: 00000000ffffffff R08: ffffffff8f9e3577 R09: 1ffffffff1f3c6ae
R10: dffffc0000000000 R11: ffffffff8194a920 R12: 0000000000000046
R13: ffff888025b61e40 R14: ffff8880308c46e8 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125cfd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555582c3c608 CR3: 000000007780c000 CR4: 00000000003526f0
Call Trace:
__lock_is_held kernel/locking/lockdep.c:5601 [inline]
lock_is_held_type+0xa8/0x190 kernel/locking/lockdep.c:5940
lock_is_held include/linux/lockdep.h:249 [inline]
select_task_rq_fair+0xa4/0x3570 kernel/sched/fair.c:8572
select_task_rq kernel/sched/core.c:3501 [inline]
try_to_wake_up+0x4d8/0x12b0 kernel/sched/core.c:4210
hrtimer_wakeup+0x4e/0x60 kernel/time/hrtimer.c:2013
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2034 [inline]
RIP: 0010:vprintk_emit+0x49d/0x590 kernel/printk/printk.c:2422
Code: 0f 84 34 ff ff ff e8 92 ee 1f 00 fb eb 44 e8 8a ee 1f 00 e8 85 39 ae 09 4d 85 f6 74 94 e8 7b ee 1f 00 fb 48 c7 c7 00 17 13 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 1b 3b
RSP: 0018:ffffc90005e36940 EFLAGS: 00000293
RAX: ffffffff81a08895 RBX: ffffffff81a086ee RCX: ffff888025b61e40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e131700
RBP: ffffc90005e36a50 R08: ffffffff8f9e3577 R09: 1ffffffff1f3c6ae
R10: dffffc0000000000 R11: fffffbfff1f3c6af R12: 0000000000000000
R13: 0000000000000073 R14: 0000000000000200 R15: 1ffff92000bc6d2c
_printk+0xcf/0x120 kernel/printk/printk.c:2448
__ext4_msg+0x293/0x2a0 fs/ext4/super.c:990
mpage_map_and_submit_extent fs/ext4/inode.c:2493 [inline]
ext4_do_writepages+0x30a6/0x4610 fs/ext4/inode.c:2931
ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
do_writepages+0x32e/0x550 mm/page-writeback.c:2604
__writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1719
writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:2015
wb_writeback+0x43b/0xaf0 fs/fs-writeback.c:2195
wb_do_writeback fs/fs-writeback.c:2342 [inline]
wb_workfn+0x409/0xef0 fs/fs-writeback.c:2382
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245