INFO: task udevd:5632 blocked in I/O wait[  429.908659][   T38] INFO: task udevd:5632 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:25128 pid:5632  tgid:5632  ppid:4947   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 io_schedule+0x80/0xe0 kernel/sched/core.c:8154
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
 __wait_on_bit_lock+0xe0/0x4a0 kernel/sched/wait_bit.c:93
 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
 wait_on_bit_lock_io include/linux/wait_bit.h:221 [inline]
 __lock_buffer fs/buffer.c:68 [inline]
 lock_buffer include/linux/buffer_head.h:434 [inline]
 block_read_full_folio+0x38f/0x810 fs/buffer.c:2417
 filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2516
 filemap_update_page mm/filemap.c:2603 [inline]
 filemap_get_pages+0x16f9/0x1e80 mm/filemap.c:2733
 filemap_read+0x429/0x11e0 mm/filemap.c:2820
 blkdev_read_iter+0x2f8/0x430 block/fops.c:830
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x59e/0xa90 fs/read_write.c:574
 ksys_read+0x156/0x270 fs/read_write.c:716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe4da3d2407
RSP: 002b:00007fff5214e0c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fe4da2e4880 RCX: 00007fe4da3d2407
RDX: 0000000000000200 RSI: 00007fe4d9995000 RDI: 0000000000000009
RBP: 000055dd1c8fe050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000008000 R14: 000055dd1c907578 R15: 00007fe4dab2839c
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by kswapd1/95:
2 locks held by getty/5336:
 #0: ffff888032e220a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
1 lock held by syz-executor352/5631:
2 locks held by udevd/5632:
 #0: ffff8880236dbe48 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1039 [inline]
 #0: ffff8880236dbe48 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_read_iter+0x2e6/0x430 block/fops.c:829
 #1: ffff8880236dc018 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
 #1: ffff8880236dc018 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_update_page mm/filemap.c:2569 [inline]
 #1: ffff8880236dc018 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_get_pages+0x936/0x1e80 mm/filemap.c:2733

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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: 5631 Comm: syz-executor352 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:lock_acquire+0x0/0x350 kernel/locking/lockdep.c:5828
Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa b0 01 c3 cc cc cc cc cc 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 60 4d 89 ce 45
RSP: 0018:ffffc900045e6fd0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff822f0cdc RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e1c3000
RBP: 1ffff920008bce18 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900045e70d8 R11: ffffffff81b0b5e0 R12: dffffc0000000000
R13: ffffffff8177725f R14: ffffc900045e7088 R15: 1ffff920008bce11
FS:  000055558394b400(0000) GS:ffff888125c45000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000560f3f851168 CR3: 00000000445dc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 rcu_read_lock include/linux/rcupdate.h:840 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
 unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4584 [inline]
 slab_alloc_node mm/slub.c:4917 [inline]
 kmem_cache_alloc_noprof+0x355/0x650 mm/slub.c:4931
 alloc_buffer_head+0x2a/0x280 fs/buffer.c:2962
 folio_alloc_buffers+0x1f9/0x6f0 fs/buffer.c:845
 grow_dev_folio fs/buffer.c:985 [inline]
 grow_buffers fs/buffer.c:1026 [inline]
 __getblk_slow fs/buffer.c:1044 [inline]
 bdev_getblk+0x2c3/0x6e0 fs/buffer.c:1439
 ext4_sb_breadahead_unmovable+0x6f/0xf0 fs/ext4/super.c:280
 __ext4_get_inode_loc+0xb03/0xf40 fs/ext4/inode.c:4974
 __ext4_get_inode_loc_noinmem fs/ext4/inode.c:5004 [inline]
 __ext4_iget+0x44e/0x45b0 fs/ext4/inode.c:5316
 __ext4_fill_super fs/ext4/super.c:5600 [inline]
 ext4_fill_super+0x4de1/0x65d0 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1640
 vfs_get_tree+0x92/0x2a0 fs/super.c:1700
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount+0x319/0xdc0 fs/namespace.c:3841
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4367
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0f342b2d2a
Code: 56 53 b8 9d 00 00 00 0f 05 83 f8 ea 75 a2 c7 05 64 0d 09 00 00 00 00 00 eb 96 e8 51 05 00 00 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe6763fca8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe6763fcc0 RCX: 00007f0f342b2d2a
RDX: 0000200000000240 RSI: 0000200000000280 RDI: 00007ffe6763fcc0
RBP: 0000200000000280 R08: 00007ffe6763fd00 R09: 00007ffe6763fd00
R10: 0000000000800003 R11: 0000000000000206 R12: 0000200000000240
R13: 0000000000000004 R14: 0000000000000003 R15: 00007ffe6763fd00
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.751 msecs