INFO: task udevd:14585 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:22496 pid:14585 tgid:14585 ppid:5196 task_flags:0x400140 flags:0x00080802 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 io_schedule+0x7f/0xd0 kernel/sched/core.c:7835 folio_wait_bit_common+0x6d8/0xbc0 mm/filemap.c:1323 folio_put_wait_locked mm/filemap.c:1492 [inline] do_read_cache_folio+0x1ad/0x590 mm/filemap.c:4083 read_mapping_folio include/linux/pagemap.h:1028 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:723 adfspart_check_POWERTEC+0x92/0xef0 block/partitions/acorn.c:454 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694 blkdev_get_whole+0x380/0x510 block/bdev.c:764 bdev_open+0x31e/0xd30 block/bdev.c:973 blkdev_open+0x470/0x610 block/fops.c:697 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f07528a7407 RSP: 002b:00007ffc7a800c00 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f0752ff6880 RCX: 00007f07528a7407 RDX: 00000000000a0800 RSI: 000055ae99333a60 RDI: ffffffffffffff9c RBP: 000055ae99320910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055ae99334fe0 R13: 000055ae9932e190 R14: 0000000000000000 R15: 000055ae99334fe0 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5589: #0: ffff8880318810a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 1 lock held by udevd/14585: #0: ffff888029d53358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:961 4 locks held by kworker/0:23/16321: ============================================= 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 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+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5178 Comm: syslogd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:103 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline] RIP: 0010:unwind_next_frame+0x528/0x23c0 arch/x86/kernel/unwind_orc.c:510 Code: 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 <49> 8d 47 fc 48 0f 47 d8 4d 0f 46 ef 48 39 dd 76 a2 e9 76 fd ff ff RSP: 0018:ffffc90002f873b8 EFLAGS: 00000287 RAX: ffffffff8176a768 RBX: ffffffff9029e2ac RCX: ffffffff9029e2a8 RDX: ffffffff9029e28c RSI: ffffffff90a60b98 RDI: ffffffff8c27ca20 RBP: ffffffff9029e2a8 R08: 0000000000000009 R09: ffffffff8e75e620 R10: ffffc90002f874e8 R11: fffff520005f0ea9 R12: ffffffff8176a786 R13: ffffffff9029e29c R14: ffffc90002f874e8 R15: ffffffff9029e2a4 FS: 00007fd512dddc80(0000) GS:ffff888125455000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe2e9934286 CR3: 00000000367b4000 CR4: 00000000003526f0 Call Trace: __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:773 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1c1/0x630 mm/slub.c:6483 skb_kfree_head net/core/skbuff.c:1078 [inline] skb_free_head net/core/skbuff.c:1090 [inline] skb_release_data+0x6f0/0x940 net/core/skbuff.c:1117 skb_release_all net/core/skbuff.c:1192 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1206 __unix_dgram_recvmsg+0x9df/0xd60 net/unix/af_unix.c:2655 sock_recvmsg_nosec net/socket.c:1071 [inline] sock_recvmsg+0x172/0x1b0 net/socket.c:1093 sock_read_iter+0x251/0x320 net/socket.c:1163 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x582/0xa70 fs/read_write.c:574 ksys_read+0x150/0x270 fs/read_write.c:717 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd512f2d407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffd28bdb9e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd512dddc80 RCX: 00007fd512f2d407 RDX: 00000000000000ff RSI: 000055ecf2921950 RDI: 0000000000000000 RBP: 000055ecf2921910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055ecf29219ac R13: 0000000000000000 R14: 000055ecf2921950 R15: 000055ecbc86cd98