INFO: task syz.6.550:8785 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.550       state:D stack:27792 pid:8785  ppid:8256   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 blkdev_put+0xff/0x760 block/bdev.c:944
 blkdev_release+0x84/0x90 block/fops.c:604
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 get_signal+0x1235/0x1400 kernel/signal.c:2678
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f341c38f749
RSP: 002b:00007f341d207038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f341c5e5fa0 RCX: 00007f341c38f749
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007f341c413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f341c5e6038 R14: 00007f341c5e5fa0 R15: 00007ffef820f5a8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
3 locks held by kworker/u4:2/42:
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90000b2fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90000b2fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8cd357c0 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:4089
2 locks held by kworker/u4:9/3459:
2 locks held by getty/5529:
 #0: ffff88802cc3e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by syz-executor/5765:
 #0: ffff888029b060e0 (&type->s_umount_key#31){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff888029b060e0 (&type->s_umount_key#31){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff888029b060e0 (&type->s_umount_key#31){++++}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by udevd/5778:
1 lock held by udevd/5781:
 #0: ffff888021ee24c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
3 locks held by kworker/u4:10/6457:
 #0: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:566
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x20ee/0x44d0 kernel/sched/core.c:6694
 #2: ffff8880b8e29598 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
1 lock held by syz.6.550/8785:
 #0: ffff888021ee24c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 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+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5126 Comm: klogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__kasan_check_read+0x0/0x20 mm/kasan/shadow.c:31
Code: 41 5c 41 5d 41 5e 41 5f 5d c3 48 c7 c7 85 9a 78 8c 4c 89 e6 eb 0a 48 c7 c7 25 13 61 8c 48 89 de e8 f5 2a 7f 08 31 ed eb d4 cc <f3> 0f 1e fa 89 f6 48 8b 0c 24 31 d2 e9 df ea ff ff 66 2e 0f 1f 84
RSP: 0018:ffffc90003277338 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 000000000000002c RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90d94500
RBP: ffffc90003277588 R08: dffffc0000000000 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: ffff88807e4228c4
R13: ffff88807e421e00 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f5684c79c80(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f38a67b7198 CR3: 000000007ef94000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hlock_class kernel/locking/lockdep.c:228 [inline]
 check_wait_context kernel/locking/lockdep.c:4773 [inline]
 __lock_acquire+0x560/0x7c80 kernel/locking/lockdep.c:5087
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
 ___slab_alloc+0x207/0x1300 mm/slub.c:3154
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc_node_track_caller+0xa2/0x230 mm/slab_common.c:1027
 kmalloc_reserve+0x116/0x240 net/core/skbuff.c:584
 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:653
 alloc_skb include/linux/skbuff.h:1284 [inline]
 alloc_skb_with_frags+0xca/0x7c0 net/core/skbuff.c:6332
 sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2821
 unix_dgram_sendmsg+0x5a1/0x1720 net/unix/af_unix.c:2001
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x46a/0x620 net/socket.c:2201
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xde/0xf0 net/socket.c:2209
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5684dc9407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fffc46eb070 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5684c79c80 RCX: 00007f5684dc9407
RDX: 000000000000003a RSI: 00007fffc46eb1b0 RDI: 0000000000000003
RBP: 00007fffc46eb5e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fffc46eb5f8
R13: 00007fffc46eb1b0 R14: 000000000000001f R15: 00007fffc46eb1b0
 </TASK>