INFO: task syz.1.1348:11431 blocked for more than 144 seconds.
      Not tainted 6.16.0-rc5-next-20250709-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1348      state:D stack:24712 pid:11431 tgid:11421 ppid:5847   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5314 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6697
 __schedule_loop kernel/sched/core.c:6775 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6790
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6847
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
 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/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a8818e929
RSP: 002b:00007f4a88f33038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f4a883b6080 RCX: 00007f4a8818e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f4a883b6080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4a883b6080 R15: 00007ffefb606268
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/9:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3322
 #1: ffffc900000e7bc0 (key_gc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3215 [inline]
 #1: ffffc900000e7bc0 (key_gc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3322
 #2: ffffffff8e141f78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #2: ffffffff8e141f78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:967
1 lock held by khungtaskd/31:
 #0: ffffffff8e13c420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13c420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13c420 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by getty/5609:
 #0: ffff8880303fb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by kworker/u8:12/6828:
1 lock held by udevd/9142:
 #0: ffff888025611358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
1 lock held by syz.1.1348/11431:
 #0: ffff888025611358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by syz.6.1701/12759:
 #0: ffffffff8e141e40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3794

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc5-next-20250709-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 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:328 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:491
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted 6.16.0-rc5-next-20250709-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events free_obj_work
RIP: 0010:stack_trace_consume_entry+0x137/0x280 kernel/stacktrace.c:95
Code: 89 de 49 89 37 41 8b 18 41 0f b6 44 15 00 84 c0 0f 85 34 01 00 00 41 3b 1e 0f 92 c0 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d <c3> cc cc cc cc cc 44 89 c1 80 e1 07 80 c1 03 38 c1 0f 8c e6 fe ff
RSP: 0018:ffffc900001e75a0 EFLAGS: 00000292
RAX: 0000000000000001 RBX: ffffc900001e7660 RCX: ce8334693d7d0500
RDX: dffffc0000000000 RSI: ffffffff81ac789c RDI: ffffc900001e7660
RBP: ffffc900001e7630 R08: ffffc900001e7670 R09: 0000000000000000
R10: ffffc900001e75f8 R11: ffffffff81ac78f0 R12: ffff88801d2c0000
R13: 0000000000000000 R14: ffffffff81ac78f0 R15: ffffc900001e75a8
FS:  0000000000000000(0000) GS:ffff888125cd4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3c1af82178 CR3: 000000006cedc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_stack_walk+0x110/0x150 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4782
 free_object_list lib/debugobjects.c:326 [inline]
 free_obj_work+0x342/0x480 lib/debugobjects.c:513
 process_one_work kernel/workqueue.c:3239 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3322
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3403
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>