INFO: task udevd:12462 blocked 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:23688 pid:12462 tgid:12462 ppid:4985 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7322
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
wait_for_reconnect drivers/block/nbd.c:1107 [inline]
nbd_handle_cmd drivers/block/nbd.c:1149 [inline]
nbd_queue_rq+0x889/0x1150 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2117
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xd36/0x1580 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2356
blk_mq_dispatch_list+0xd11/0xe10 include/linux/spinlock.h:-1
blk_mq_flush_plug_list+0x45f/0x540 block/blk-mq.c:2966
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1273
blk_finish_plug block/blk-core.c:1300 [inline]
__submit_bio+0x465/0x560 block/blk-core.c:690
__submit_bio_noacct_mq block/blk-core.c:763 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:797
bh_submit fs/buffer.c:1239 [inline]
block_read_full_folio+0x581/0x810 fs/buffer.c:2449
filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2513
do_read_cache_folio+0x354/0x590 mm/filemap.c:4118
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:357
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x851/0x17a0 block/partitions/core.c:695
blkdev_get_whole+0x372/0x510 block/bdev.c:751
bdev_open+0x324/0xd70 block/bdev.c:960
blkdev_open+0x461/0x600 block/fops.c:672
do_dentry_open+0x816/0x1380 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4700 [inline]
path_openat+0x2e44/0x3830 fs/namei.c:4859
do_file_open+0x23e/0x4a0 fs/namei.c:4888
do_sys_openat2+0x115/0x200 fs/open.c:1395
do_sys_open fs/open.c:1401 [inline]
__do_sys_openat fs/open.c:1417 [inline]
__se_sys_openat fs/open.c:1412 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1412
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: 0033:0x7fb7134a7407
RSP: 002b:00007ffceb4bfa60 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fb713b4b880 RCX: 00007fb7134a7407
RDX: 00000000000a0800 RSI: 00005638eac48760 RDI: ffffffffffffff9c
RBP: 00005638eac30910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005638eac431a0
R13: 00005638eac3e190 R14: 0000000000000000 R15: 00005638eac431a0
INFO: lockdep is turned off.
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 05/09/2026
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+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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 20644 Comm: syz.3.11966 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
RIP: 0010:rcu_read_lock include/linux/rcupdate.h:840 [inline]
RIP: 0010:class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
RIP: 0010:unwind_next_frame+0x9f/0x2550 arch/x86/kernel/unwind_orc.c:495
Code: 84 46 02 00 00 89 44 24 5c 4c 89 6c 24 68 e8 b8 fc 34 00 4c 8d 2d 00 00 00 00 48 c7 c7 20 9a 95 8e 31 f6 31 d2 b9 02 00 00 00 <45> 31 c0 45 31 c9 41 55 e8 f4 1d 2b 00 48 83 c4 08 e8 3b 28 31 0a
RSP: 0018:ffffc90008d6efc0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff81aedaa4 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e959a20
RBP: 1ffff920011ade14 R08: ffffc90008d6f130 R09: 000000000000000c
R10: ffffc90008d6f0b8 R11: ffffffff81b10630 R12: dffffc0000000000
R13: ffffffff8176a21f R14: ffffc90008d6f068 R15: 1ffff920011ade0d
FS: 0000000000000000(0000) GS:ffff88812537c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556e26099ee8 CR3: 000000000e746000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1397 [inline]
free_unref_folios+0xdb2/0x14d0 mm/page_alloc.c:2999
folios_put_refs+0xa59/0xba0 mm/swap.c:1008
free_pages_and_swap_cache+0x2ba/0x490 mm/swap_state.c:401
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:417 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:424
tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549
exit_mmap+0x4b2/0x9f0 mm/mmap.c:1313
__mmput+0x118/0x420 kernel/fork.c:1181
exit_mm+0x221/0x2d0 kernel/exit.c:610
do_exit+0x6cd/0x2360 kernel/exit.c:992
do_group_exit+0x22d/0x2f0 kernel/exit.c:1147
get_signal+0x121b/0x12c0 kernel/signal.c:3038
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd0beb9ce59
Code: Unable to access opcode bytes at 0x7fd0beb9ce2f.
RSP: 002b:00007ffd6caaccf8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffd6caacde0 RCX: 00007fd0beb9ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000113d6f R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2f820000 R11: 0000000000000246 R12: 00007ffd6caace20
R13: 00007fd0bee15fac R14: 0000000000113de5 R15: 00007fd0bee15fa0