INFO: task syz-executor:5831 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21256 pid:5831  tgid:5831  ppid:1      task_flags:0x40014c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5262 [inline]
 __schedule+0x1836/0x4ed0 kernel/sched/core.c:6870
 __schedule_loop kernel/sched/core.c:6952 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6967
 wb_wait_for_completion+0x360/0x680 fs/fs-writeback.c:226
 sync_inodes_sb+0x1c9/0xb40 fs/fs-writeback.c:2894
 sync_filesystem+0x17a/0x230 fs/sync.c:64
 generic_shutdown_super+0x6f/0x2c0 fs/super.c:622
 kill_block_super+0x44/0x90 fs/super.c:1728
 ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7404
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1328
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6bd/0x2300 kernel/exit.c:970
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1111
 __do_sys_exit_group kernel/exit.c:1122 [inline]
 __se_sys_exit_group kernel/exit.c:1120 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1120
 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232
 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: 0033:0x7f852f58f6c9
RSP: 002b:00007fffd7420928 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f852f611def RCX: 00007f852f58f6c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000010 R08: 00007fffd741e6c6 R09: 00007fffd7421be0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffd7421be0
R13: 00007f852f611d7d R14: 0000555591d714a8 R15: 00007fffd7422cb0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:2/36:
2 locks held by getty/5587:
 #0: ffff88803542a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036be2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/5831:
 #0: ffff888079a3c0e0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888079a3c0e0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888079a3c0e0 (&type->s_umount_key#32){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffff888024ff8820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline]
 #1: ffff888024ff8820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1ad/0xb40 fs/fs-writeback.c:2892
4 locks held by kworker/u8:9/5967:
 #0: ffff8880b863a3d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646
 #1: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #1: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #1: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
 #1: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4a0 kernel/trace/bpf_trace.c:2118
 #2: ffff88814175f0e0 (&lo->lo_work_lock){..-.}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:376 [inline]
 #2: ffff88814175f0e0 (&lo->lo_work_lock){..-.}-{3:3}, at: loop_process_work+0xfd/0xf90 drivers/block/loop.c:1951
 #3: ffff8880b863a3d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646
2 locks held by kworker/u8:14/7371:
 #0: ffff8880b863a3d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646
 #1: ffffffff8df3d560 (rcu_read_lock){....}-{1:3}, at: debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873
1 lock held by syz.4.497/7665:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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:336 [inline]
 watchdog+0xfa8/0xff0 kernel/hung_task.c:499
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 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: 7665 Comm: syz.4.497 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:task_wait_context kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4875 [inline]
RIP: 0010:__lock_acquire+0x5b1/0xd20 kernel/locking/lockdep.c:5187
Code: 89 d0 e9 4a ff ff ff 48 c7 c7 70 df e0 8d 48 89 de e8 43 f0 29 03 48 8b 3c 24 e9 56 ff ff ff 83 bf 14 0b 00 00 00 41 0f 94 c4 <45> 00 e4 41 80 c4 03 44 3b bf 28 0b 00 00 0f 8c fc fe ff ff 44 89
RSP: 0018:ffffc90011ecf1c8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000ffffffff
RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffff8880254c0000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81742fd5
R10: ffffc90011ecf418 R11: ffffffff81ad9810 R12: ffffffffffffff01
R13: 0000000000000001 R14: ffff8880254c0b80 R15: 0000000000000000
FS:  0000555581187500(0000) GS:ffff888125fc1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe8cd142d58 CR3: 000000007def6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire+0x117/0x350 kernel/locking/lockdep.c:5868
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4950 [inline]
 slab_alloc_node mm/slub.c:5260 [inline]
 kmem_cache_alloc_noprof+0x37d/0x700 mm/slub.c:5267
 kmem_alloc_batch lib/debugobjects.c:371 [inline]
 fill_pool+0x100/0x570 lib/debugobjects.c:403
 debug_objects_fill_pool lib/debugobjects.c:725 [inline]
 debug_object_activate+0x383/0x420 lib/debugobjects.c:814
 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
 debug_activate kernel/time/hrtimer.c:477 [inline]
 enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1081
 __hrtimer_start_range_ns kernel/time/hrtimer.c:1263 [inline]
 hrtimer_start_range_ns+0xcea/0x1080 kernel/time/hrtimer.c:1322
 futex_do_wait kernel/futex/waitwake.c:345 [inline]
 __futex_wait+0x16c/0x3d0 kernel/futex/waitwake.c:687
 futex_wait+0x104/0x360 kernel/futex/waitwake.c:715
 do_futex+0x333/0x420 kernel/futex/syscalls.c:130
 __do_sys_futex kernel/futex/syscalls.c:207 [inline]
 __se_sys_futex+0x36f/0x400 kernel/futex/syscalls.c:188
 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: 0033:0x7fe8cc38f6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff75a975b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 000000000003dfc6 RCX: 00007fe8cc38f6c9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe8cc5e618c
RBP: 0000000000000032 R08: 3fffffffffffffff R09: 0000000e75a978af
R10: 00007fff75a976b0 R11: 0000000000000246 R12: 00007fe8cc5e618c
R13: 00007fff75a976b0 R14: 000000000003dff8 R15: 00007fff75a976d0
 </TASK>