INFO: task udevd:32727 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:22344 pid:32727 tgid:32727 ppid:4994 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+0x785/0x14e0 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+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1f864a7407 RSP: 002b:00007ffe193a3c10 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f1f86b54880 RCX: 00007f1f864a7407 RDX: 00000000000a0800 RSI: 000055fab707e520 RDI: ffffffffffffff9c RBP: 000055fab707d910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055fab709af10 R13: 000055fab708b190 R14: 0000000000000000 R15: 000055fab709af10 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:5/112: #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: ffffc90002627c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90002627c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdd2400 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 2 locks held by syslogd/4976: #0: ffff8880b873aea0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:652 #1: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933 2 locks held by getty/5384: #0: ffff8880358700a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211 3 locks held by kworker/u8:16/7590: #0: ffff8880316af140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff8880316af140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90004e7fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90004e7fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdd2400 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8fdd2400 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4213 1 lock held by udevd/32727: #0: ffff888026b01350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953 2 locks held by syz.4.10172/10616: #0: ffff88805898d640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline] #0: ffff88805898d640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline] #0: ffff88805898d640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514 #1: ffffffff8fdd2400 (rtnl_mutex){+.+.}-{4:4}, at: raw_release+0x1bc/0x9f0 net/can/raw.c:430 1 lock held by syz.2.10177/10624: #0: ffff8880766b5640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline] #0: ffff8880766b5640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline] #0: ffff8880766b5640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514 4 locks held by syz.2.10177/10626: 2 locks held by syz.0.10178/10628: #0: ffffffff8fdd5cc0 (bpf_dispatcher_xdp.mutex){+.+.}-{4:4}, at: bpf_dispatcher_change_prog+0xc6/0xd70 kernel/bpf/dispatcher.c:146 #1: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961 1 lock held by syz.1.10179/10632: #0: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #0: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961 1 lock held by syz.3.10180/10635: #0: ffffffff8fdd2400 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:641 [inline] #0: ffffffff8fdd2400 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3502 ============================================= 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 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 10626 Comm: syz.2.10177 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline] RIP: 0010:mark_lock+0x3c/0x190 kernel/locking/lockdep.c:4731 Code: 00 03 00 83 f9 01 bb 09 00 00 00 83 db 00 83 fa 08 0f 45 da bd 01 00 00 00 89 d9 d3 e5 25 ff 1f 00 00 48 0f a3 05 a4 6f a0 12 <73> 10 48 69 c0 c8 00 00 00 48 8d 88 70 73 e3 93 eb 42 83 3d 6b ff RSP: 0018:ffffc9000d55ee48 EFLAGS: 00000003 RAX: 0000000000000007 RBX: 0000000000000009 RCX: 0000000000000009 RDX: 0000000000000008 RSI: ffff88802f3de820 RDI: ffff88802f3ddc40 RBP: 0000000000000200 R08: ffffffff8a59b5ea R09: ffffffff8e95cca0 R10: dffffc0000000000 R11: ffffffff8a59b500 R12: 0000000000000003 R13: ffff88802f3de820 R14: ffff88802f3ddc40 R15: 0000000000000002 FS: 00007f52ac8ae6c0(0000) GS:ffff888125376000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000012c0 CR3: 000000004d248000 CR4: 00000000003526f0 Call Trace: mark_usage kernel/locking/lockdep.c:4674 [inline] __lock_acquire+0x6b5/0x2cf0 kernel/locking/lockdep.c:5191 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] ip6_link_failure+0x106/0x4c0 net/ipv6/route.c:2866 dst_link_failure include/net/dst.h:438 [inline] vti_xmit net/ipv4/ip_vti.c:271 [inline] vti_tunnel_xmit+0x10a4/0x1a00 net/ipv4/ip_vti.c:307 __netdev_start_xmit include/linux/netdevice.h:5379 [inline] netdev_start_xmit include/linux/netdevice.h:5388 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904 __dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4871 dev_queue_xmit include/linux/netdevice.h:3429 [inline] __bpf_tx_skb net/core/filter.c:2156 [inline] __bpf_redirect_no_mac net/core/filter.c:2186 [inline] __bpf_redirect+0x9a6/0x12a0 net/core/filter.c:2209 ____bpf_clone_redirect net/core/filter.c:2497 [inline] bpf_clone_redirect+0x313/0x4b0 net/core/filter.c:2460 bpf_prog_69c2527fbc57d46b+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:722 [inline] bpf_prog_run include/linux/filter.h:729 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0xe2c/0x2260 net/bpf/test_run.c:1192 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4742 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6266 __do_sys_bpf kernel/bpf/syscall.c:6361 [inline] __se_sys_bpf kernel/bpf/syscall.c:6359 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6359 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f52ab99ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f52ac8ae028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f52abc15fa0 RCX: 00007f52ab99ce59 RDX: 0000000000000050 RSI: 0000200000002300 RDI: 000000000000000a RBP: 00007f52aba32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f52abc16038 R14: 00007f52abc15fa0 R15: 00007ffd0d8ad0d8 ---------------- Code disassembly (best guess): 0: 00 03 add %al,(%rbx) 2: 00 83 f9 01 bb 09 add %al,0x9bb01f9(%rbx) 8: 00 00 add %al,(%rax) a: 00 83 db 00 83 fa add %al,-0x57cff25(%rbx) 10: 08 0f or %cl,(%rdi) 12: 45 da bd 01 00 00 00 rex.RB fidivrl 0x1(%r13) 19: 89 d9 mov %ebx,%ecx 1b: d3 e5 shl %cl,%ebp 1d: 25 ff 1f 00 00 and $0x1fff,%eax 22: 48 0f a3 05 a4 6f a0 bt %rax,0x12a06fa4(%rip) # 0x12a06fce 29: 12 * 2a: 73 10 jae 0x3c <-- trapping instruction 2c: 48 69 c0 c8 00 00 00 imul $0xc8,%rax,%rax 33: 48 8d 88 70 73 e3 93 lea -0x6c1c8c90(%rax),%rcx 3a: eb 42 jmp 0x7e 3c: 83 .byte 0x83 3d: 3d .byte 0x3d 3e: 6b .byte 0x6b 3f: ff .byte 0xff