INFO: task syz.6.6739:30911 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.6739      state:D stack:26360 pid:30911 tgid:30910 ppid:26398  task_flags:0x400140 flags:0x00080802
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0xfee/0x60e0 kernel/sched/core.c:6907
 __schedule_loop kernel/sched/core.c:6989 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7004
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 sync_bdevs+0x153/0x480 block/bdev.c:1304
 ksys_sync+0xb0/0xf0 fs/sync.c:105
 __do_sys_sync+0xe/0x20 fs/sync.c:111
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f329619c629
RSP: 002b:00007f3296f74028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f3296415fa0 RCX: 00007f329619c629
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f3296415fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3296416038 R14: 00007f3296415fa0 R15: 00007ffdb61a9218
 </TASK>
INFO: task syz.6.6739:30914 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.6739      state:D stack:29000 pid:30914 tgid:30910 ppid:26398  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0xfee/0x60e0 kernel/sched/core.c:6907
 __schedule_loop kernel/sched/core.c:6989 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7004
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 sync_bdevs+0x153/0x480 block/bdev.c:1304
 ksys_sync+0xb0/0xf0 fs/sync.c:105
 __do_sys_sync+0xe/0x20 fs/sync.c:111
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f329619c629
RSP: 002b:00007f32943f6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f3296416090 RCX: 00007f329619c629
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f3296416090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3296416128 R14: 00007f3296416090 R15: 00007ffdb61a9218
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/5564:
 #0: ffff8880344fd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
4 locks held by kworker/u8:31/12000:
 #0: ffff8880b843b1a0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:655 [inline]
 #0: ffff8880b843b1a0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:639
 #1: ffff8880b8424648 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:225 [inline]
 #1: ffff8880b8424648 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2c11/0x60e0 kernel/sched/core.c:6901
 #2: ffff8880b8426358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x124/0x1d0 kernel/time/timer.c:1004
 #3: ffffffff9b3c41f0 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x144/0x490 lib/debugobjects.c:818
1 lock held by udevd/28741:
 #0: ffff888028046358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:961
1 lock held by syz.6.6739/30911:
 #0: ffff888028046358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x153/0x480 block/bdev.c:1304
1 lock held by syz.6.6739/30914:
 #0: ffff888028046358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x153/0x480 block/bdev.c:1304

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xd25/0x1050 kernel/hung_task.c:515
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: d8 82 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 43 0c 1c 00 fb f4 <e9> bc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e407e00 EFLAGS: 00000242
RAX: 0000000006903bd5 RBX: ffffffff8e4975c0 RCX: ffffffff8b8f7c75
RDX: 0000000000000000 RSI: ffffffff8de7237c RDI: ffffffff8c1af120
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1017086795
R10: ffff8880b8433cab R11: 0000000000000000 R12: fffffbfff1c92eb8
R13: 0000000000000000 R14: ffffffff90d96710 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124348000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f874ee0660 CR3: 000000000e598000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000db67 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:73 [inline]
 default_idle+0x9/0x10 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x35b/0x4b0 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 rest_init+0x251/0x260 init/main.c:760
 start_kernel+0x47f/0x480 init/main.c:1210
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x148
 </TASK>