INFO: task udevd:5788 blocked in I/O wait for more than 1[ 594.239909][ T38] INFO: task udevd:5788 blocked in I/O wait for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:22024 pid:5788 tgid:5788 ppid:4958 task_flags:0x400140 flags:0x00080802
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7282
io_schedule+0x80/0xe0 kernel/sched/core.c:8109
folio_wait_bit_common+0x6dd/0xbc0 mm/filemap.c:1324
folio_put_wait_locked mm/filemap.c:1493 [inline]
do_read_cache_folio+0x1a7/0x560 mm/filemap.c:4089
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb8/0x2b0 block/partitions/core.c:724
adfspart_check_POWERTEC+0x9a/0x7a0 block/partitions/acorn.c:450
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x817/0x1770 block/partitions/core.c:695
blkdev_get_whole+0x2e5/0x480 block/bdev.c:756
bdev_open+0x31e/0xcc0 block/bdev.c:965
blkdev_open+0x485/0x620 block/fops.c:697
do_dentry_open+0x83d/0x13e0 fs/open.c:947
vfs_open+0x3b/0x350 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e43/0x38a0 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff0c405d407
RSP: 002b:00007ffdba607ec0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff0c3f6f880 RCX: 00007ff0c405d407
RDX: 00000000000a0800 RSI: 000055cc430a2a10 RDI: ffffffffffffff9c
RBP: 000055cc43089910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055cc430da1b0
R13: 000055cc43097190 R14: 0000000000000000 R15: 000055cc430da1b0
INFO: task udevd:5906 blocked in I/O wait for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:20952 pid:5906 tgid:5906 ppid:4958 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7282
io_schedule+0x80/0xe0 kernel/sched/core.c:8109
folio_wait_bit_common+0x6dd/0xbc0 mm/filemap.c:1324
folio_put_wait_locked mm/filemap.c:1493 [inline]
do_read_cache_folio+0x1a7/0x560 mm/filemap.c:4089
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb8/0x2b0 block/partitions/core.c:724
adfspart_check_POWERTEC+0x9a/0x7a0 block/partitions/acorn.c:450
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x817/0x1770 block/partitions/core.c:695
blkdev_get_whole+0x2e5/0x480 block/bdev.c:756
bdev_open+0x31e/0xcc0 block/bdev.c:965
blkdev_open+0x485/0x620 block/fops.c:697
do_dentry_open+0x83d/0x13e0 fs/open.c:947
vfs_open+0x3b/0x350 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e43/0x38a0 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff0c405d407
RSP: 002b:00007ffdba607ec0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff0c3f6f880 RCX: 00007ff0c405d407
RDX: 00000000000a0800 RSI: 000055cc430b2f10 RDI: ffffffffffffff9c
RBP: 000055cc43089910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055cc43091650
R13: 000055cc43097190 R14: 0000000000000000 R15: 000055cc43091650
Showing all locks held in the system:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:5/68:
#0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc9000153fc40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc9000153fc40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
2 locks held by udevd/4958:
2 locks held by getty/5349:
#0: ffff88803314a0a0 (&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+0x462/0x13a0 drivers/tty/n_tty.c:2211
9 locks held by syz-executor/5592:
9 locks held by syz-executor/5600:
1 lock held by udevd/5788:
#0: ffff8880269bb4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
2 locks held by kworker/u8:14/5864:
#0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc900051cfc40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc900051cfc40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
1 lock held by udevd/5906:
#0: ffff8880269fb4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by udevd/6266:
1 lock held by syz.4.1612/11242:
1 lock held by syz.0.1620/11258:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
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+0xfd3/0x1030 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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 ee 47 90 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 4f 51 f7 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 da df eb 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff3362a00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99b15930 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85342900 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b156a0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812627a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf24273ff8 CR3: 0000000039298000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline]
serial8250_console_write+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3357
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
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
----------------
Code disassembly (best guess):
0: e8 ee 47 90 fc call 0xfc9047f3
5: 44 89 f9 mov %r15d,%ecx
8: d3 e3 shl %cl,%ebx
a: 49 83 ee 80 sub $0xffffffffffffff80,%r14
e: 4c 89 f0 mov %r14,%rax
11: 48 c1 e8 03 shr $0x3,%rax
15: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1)
1a: 74 08 je 0x24
1c: 4c 89 f7 mov %r14,%rdi
1f: e8 4f 51 f7 fc call 0xfcf75173
24: 41 03 1e add (%r14),%ebx
27: 89 da mov %ebx,%edx
29: ec in (%dx),%al
* 2a: 0f b6 c0 movzbl %al,%eax <-- trapping instruction
2d: 5b pop %rbx
2e: 41 5c pop %r12
30: 41 5e pop %r14
32: 41 5f pop %r15
34: e9 da df eb 05 jmp 0x5ebe013
39: cc int3
3a: 44 89 f9 mov %r15d,%ecx
3d: 80 e1 07 and $0x7,%cl