INFO: task udevd:5803 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:23528 pid:5803 ppid:5159 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 io_schedule+0x80/0xd0 kernel/sched/core.c:9022 folio_wait_bit_common+0x6eb/0xf70 mm/filemap.c:1329 folio_put_wait_locked mm/filemap.c:1493 [inline] do_read_cache_folio+0x1c0/0x7e0 mm/filemap.c:3771 read_mapping_folio include/linux/pagemap.h:898 [inline] read_part_sector+0xd2/0x350 block/partitions/core.c:718 adfspart_check_POWERTEC+0x8d/0xf00 block/partitions/acorn.c:454 check_partition block/partitions/core.c:138 [inline] blk_add_partitions block/partitions/core.c:600 [inline] bdev_disk_changed+0x73a/0x1410 block/partitions/core.c:689 blkdev_get_whole+0x30d/0x390 block/bdev.c:655 blkdev_get_by_dev+0x279/0x600 block/bdev.c:797 blkdev_open+0x152/0x360 block/fops.c:589 do_dentry_open+0x8c6/0x1500 fs/open.c:929 do_open fs/namei.c:3632 [inline] path_openat+0x274b/0x3190 fs/namei.c:3789 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419 do_sys_open fs/open.c:1434 [inline] __do_sys_openat fs/open.c:1450 [inline] __se_sys_openat fs/open.c:1445 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1445 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7faeb58a7407 RSP: 002b:00007ffc7f5e55c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007faeb5ffd880 RCX: 00007faeb58a7407 RDX: 00000000000a0800 RSI: 00005622294e6ce0 RDI: ffffffffffffff9c RBP: 00005622294d7910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00005622294efe00 R13: 00005622294ef410 R14: 0000000000000000 R15: 00005622294efe00 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by getty/5554: #0: ffff88814c9b50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217 1 lock held by udevd/5803: #0: ffff888021bb24c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788 1 lock held by dhcpcd-run-hook/14390: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf41/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 14395 Comm: sed Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:userfaultfd_unmap_prep+0x4/0x3d0 fs/userfaultfd.c:849 Code: ef e8 e0 36 dc ff e9 5a fe ff ff f3 0f 1e fa e8 d2 eb 84 ff 4c 89 e7 31 f6 e8 b8 0c c6 ff e9 09 ff ff ff 0f 1f 00 66 0f 1f 00 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 10 48 89 cb 49 89 d5 48 89 RSP: 0018:ffffc9000b6df7f8 EFLAGS: 00000286 RAX: ffffffff81cb7c3c RBX: 0000000000000000 RCX: ffffc9000b6dfea0 RDX: 00007fb8f28d7000 RSI: 00007fb8f28d5000 RDI: ffff8880663d0500 RBP: ffffc9000b6dfa50 R08: ffff88807e032737 R09: 1ffff1100fc064e6 R10: dffffc0000000000 R11: ffffed100fc064e7 R12: dffffc0000000000 R13: 00007fb8f28d7000 R14: 00007fb8f28d5000 R15: ffff8880663d0500 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb8f28d4068 CR3: 000000002e8e6000 CR4: 00000000003506e0 Call Trace: do_vmi_align_munmap+0x7dd/0x1660 mm/mmap.c:2538 do_vmi_munmap+0x252/0x2d0 mm/mmap.c:2660 __mmap_region mm/mmap.c:2710 [inline] mmap_region+0x741/0x2020 mm/mmap.c:2941 do_mmap+0x92f/0x10a0 mm/mmap.c:1385 vm_mmap_pgoff+0x1c0/0x400 mm/util.c:556 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb8f2bc6242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007ffe165db068 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fb8f28d5000 RCX: 00007fb8f2bc6242 RDX: 0000000000000003 RSI: 00000000000016d0 RDI: 00007fb8f28d5000 RBP: 0000000000000032 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000032 R11: 0000000000000206 R12: 00007ffe165db128 R13: 00007fb8f2ba3ab0 R14: 00007ffe165db4e0 R15: 00007fb8f28d5000