INFO: task udevd:5652 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:21816 pid:5652 tgid:5652 ppid:4999 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
io_schedule+0x7f/0xd0 kernel/sched/core.c:8110
folio_wait_bit_common+0x6d8/0xbc0 mm/filemap.c:1324
folio_put_wait_locked mm/filemap.c:1493 [inline]
do_read_cache_folio+0x1ad/0x590 mm/filemap.c:4089
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb6/0x2b0 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+0x380/0x510 block/bdev.c:756
bdev_open+0x31e/0xd30 block/bdev.c:965
blkdev_open+0x470/0x610 block/fops.c:697
do_dentry_open+0x822/0x13a0 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e08/0x3860 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+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd5eaea7407
RSP: 002b:00007ffd22e03190 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fd5eb60d880 RCX: 00007fd5eaea7407
RDX: 00000000000a0800 RSI: 000056478c28e150 RDI: ffffffffffffff9c
RBP: 000056478c27c910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000056478c290ba0
R13: 000056478c28a190 R14: 0000000000000000 R15: 000056478c290ba0
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:4/64:
2 locks held by getty/5388:
#0: ffff8880362e00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by udevd/5652:
#0: ffff888026ef6350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953
3 locks held by kworker/u8:13/9199:
#0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000ed57c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000ed57c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by syz.3.4120/18881:
2 locks held by syz.0.4138/18914:
#0: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3438
#1: ffffffff8e962fe8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8e962fe8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
1 lock held by syz.6.4140/18918:
#0: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x722/0xbe0 net/core/rtnetlink.c:7003
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(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+0x389/0x470 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 18881 Comm: syz.3.4120 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:should_fail_ex+0x4/0x560 lib/fault-inject.c:125
Code: 8f 4c 89 f2 31 c9 e8 2b f3 c4 ff eb cf 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 18 89 14 24 49 89 f6 48 89
RSP: 0018:ffffc90004d5e4e8 EFLAGS: 00000293
RAX: 0000000000000001 RBX: ffffc90004d5e5a0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8eaa3720
RBP: 0000000000000008 R08: ffffffff8223aa4c R09: ffffffff8ea9aaa0
R10: ffffc90004d5e5a0 R11: fffff520009abcb9 R12: 1ffff920009abcaf
R13: ffff88802a429f2c R14: 0000000000140cca R15: 1ffff920009abcb4
FS: 00007f9ef46da6c0(0000) GS:ffff88812529a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffa43fea2f8 CR3: 00000000299c2000 CR4: 00000000003526f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
prepare_alloc_pages+0x22a/0x650 mm/page_alloc.c:5002
__alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5215
alloc_pages_mpol+0x235/0x490 mm/mempolicy.c:2490
folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2509
shmem_alloc_folio mm/shmem.c:1933 [inline]
shmem_alloc_and_add_folio+0x442/0xf80 mm/shmem.c:1975
shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2564
shmem_get_folio mm/shmem.c:2670 [inline]
shmem_write_begin+0x16c/0x330 mm/shmem.c:3303
generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4325
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3478
__kernel_write_iter+0x41e/0x880 fs/read_write.c:621
dump_emit_page fs/coredump.c:1304 [inline]
dump_user_range+0xc19/0x12c0 fs/coredump.c:1378
elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2109
coredump_write+0x1216/0x1910 fs/coredump.c:1053
do_coredump fs/coredump.c:1132 [inline]
vfs_coredump+0x3807/0x4530 fs/coredump.c:1206
get_signal+0x1107/0x1330 kernel/signal.c:3022
arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
irqentry_exit+0x2aa/0x8b0 kernel/entry/common.c:162
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 002b:00002000000001d8 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f9ef3a16090 RCX: 00007f9ef379ce59
RDX: 0000200000000300 RSI: 00002000000001d0 RDI: 0000000020000000
RBP: 00007f9ef3832d6f R08: 00002000000003c0 R09: 00002000000003c0
R10: 0000200000000380 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f9ef3a16128 R14: 00007f9ef3a16090 R15: 00007fff21cfebf8
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 4c 89 f2 mov %r14,%rdx
3: 31 c9 xor %ecx,%ecx
5: e8 2b f3 c4 ff call 0xffc4f335
a: eb cf jmp 0xffffffdb
c: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
13: 00 00
15: 90 nop
16: 90 nop
17: 90 nop
18: 90 nop
19: 90 nop
1a: 90 nop
1b: 90 nop
1c: 90 nop
1d: 90 nop
1e: 90 nop
1f: 90 nop
20: 90 nop
21: 90 nop
22: 90 nop
23: 90 nop
24: 90 nop
25: 0f 1f 40 d6 nopl -0x2a(%rax)
* 29: 55 push %rbp <-- trapping instruction
2a: 41 57 push %r15
2c: 41 56 push %r14
2e: 41 55 push %r13
30: 41 54 push %r12
32: 53 push %rbx
33: 48 83 ec 18 sub $0x18,%rsp
37: 89 14 24 mov %edx,(%rsp)
3a: 49 89 f6 mov %rsi,%r14
3d: 48 rex.W
3e: 89 .byte 0x89