INFO: task udevd:3038 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:23480 pid:3038 tgid:3038 ppid:5188 task_flags:0x40054c flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1568/0x5290 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 io_schedule+0x7f/0xd0 kernel/sched/core.c:7831 folio_wait_bit_common+0x6d8/0xbc0 mm/filemap.c:1323 __folio_lock mm/filemap.c:1699 [inline] folio_lock include/linux/pagemap.h:1170 [inline] __filemap_get_folio_mpol+0x13e/0xb00 mm/filemap.c:1954 __filemap_get_folio include/linux/pagemap.h:774 [inline] truncate_inode_pages_range+0x48b/0xe30 mm/truncate.c:413 kill_bdev block/bdev.c:91 [inline] blkdev_flush_mapping+0x109/0x2f0 block/bdev.c:728 blkdev_put_whole block/bdev.c:735 [inline] bdev_release+0x417/0x650 block/bdev.c:1160 blkdev_release+0x15/0x20 block/fops.c:706 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x69b/0x2310 kernel/exit.c:971 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1132aa7407 RSP: 002b:00007ffdc84c28f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: fffffffffffffffc RBX: 00007f113319d880 RCX: 00007f1132aa7407 RDX: 0000000000000200 RSI: 00007f113319c000 RDI: 0000000000000009 RBP: 000055b320951050 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 000055b320961fb8 R15: 00007f11332c439c Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e75e0a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75e0a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75e0a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5578: #0: ffff8880376720a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 1 lock held by udevd/3038: #0: ffff8880270ee358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1a9/0x650 block/bdev.c:1144 1 lock held by sed/16014: ============================================= 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 02/12/2026 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:161 [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:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 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: 16017 Comm: rm Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:98 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:115 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x97/0x2c0 mm/kasan/generic.c:200 Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 3d 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 9e 01 00 00 49 ff c3 48 ff c3 75 ee e9 1d 01 00 00 44 89 dd RSP: 0000:ffffc9000ea47b38 EFLAGS: 00000246 RAX: 0000000000000601 RBX: ffffffffffffffff RCX: ffffffff82357f9e RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88801c6c36a8 RBP: ffff8880b8741c50 R08: ffff88801c6c36ab R09: 1ffff110038d86d5 R10: dffffc0000000000 R11: ffffed10038d86d5 R12: 0000000000000001 R13: ffffffff93191c40 R14: ffffed10038d86d6 R15: 1ffff110038d86d5 FS: 00007fde6003cc80(0000) GS:ffff8881255b0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fde6013d340 CR3: 00000000a2e50000 CR4: 00000000003526f0 Call Trace: instrument_atomic_read include/linux/instrumented.h:68 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] memcg_vmstats_needs_flush mm/memcontrol.c:563 [inline] memcg_rstat_updated+0xee/0x220 mm/memcontrol.c:586 count_memcg_events+0xc5/0x240 mm/memcontrol.c:857 count_memcg_events_mm include/linux/memcontrol.h:989 [inline] count_memcg_event_mm+0x14c/0x260 include/linux/memcontrol.h:996 mm_account_fault mm/memory.c:6448 [inline] handle_mm_fault+0x2b96/0x32a0 mm/memory.c:6609 do_user_addr_fault+0xa73/0x1360 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7fde6013d340 Code: 84 00 00 00 00 00 0f 1f 40 00 48 8b 05 89 8a 19 00 64 48 03 04 25 00 00 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <48> 8b 05 11 8c 19 00 48 8b 0d 72 8a 19 00 64 48 8b 00 48 8b 00 48 RSP: 002b:00007ffc977058a8 EFLAGS: 00010202 RAX: 00007fde601137e8 RBX: 0000000000000001 RCX: 00007fde601137e8 RDX: 00007fde602509b0 RSI: 00007fde603da980 RDI: 0000000000000001 RBP: 00007ffc97705b80 R08: 0000000000000000 R09: 000000000000000e R10: fffffffffffff68e R11: 0000000000000206 R12: fffffffffffffff8 R13: 00000484a6fca70e R14: 0000000000000000 R15: 00007fde603e7310