INFO: task udevd:21028 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:23400 pid:21028 tgid:21028 ppid:5194 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7183 __schedule_loop kernel/sched/core.c:7262 [inline] schedule+0x164/0x360 kernel/sched/core.c:7277 schedule_timeout+0x158/0x2c0 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+0x857/0x1100 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0xa70/0x1910 block/blk-mq.c:2148 __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+0xdcc/0x1600 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:2386 blk_mq_dispatch_list+0xd16/0xe10 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997 __blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230 blk_finish_plug block/blk-core.c:1257 [inline] __submit_bio+0x28d/0x580 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:753 submit_bh fs/buffer.c:2735 [inline] block_read_full_folio+0x7b7/0x830 fs/buffer.c:2351 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501 do_read_cache_folio+0x358/0x590 mm/filemap.c:4106 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:356 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: 0033:0x7f9d348a7407 RSP: 002b:00007ffe1511f820 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f9d34fc3880 RCX: 00007f9d348a7407 RDX: 00000000000a0800 RSI: 000055616b6d5340 RDI: ffffffffffffff9c RBP: 000055616b6d4910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055616b6f9970 R13: 000055616b6e2190 R14: 0000000000000000 R15: 000055616b6f9970 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 1 lock held by syslogd/5176: #0: ffff8880b873aea0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647 2 locks held by getty/5581: #0: ffff888036fdf0a0 (&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 2 locks held by kworker/1:12/18885: #0: ffff8880b873aea0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647 #1: ffff8880b8724588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933 1 lock held by udevd/21027: #0: ffff888026e66350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953 3 locks held by udevd/21028: #0: ffff888026dff350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953 #1: ffff88802642ee98 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline] #1: ffff88802642ee98 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline] #1: ffff88802642ee98 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0 block/blk-mq.c:2386 #2: ffff888026eb51f8 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199 1 lock held by syz.1.5348/27271: #0: ffff888038411140 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline] #0: ffff888038411140 (&dev->mutex){....}-{4:4}, at: nfc_unregister_rfkill+0x63/0x280 net/nfc/core.c:1166 4 locks held by syz.1.5348/27273: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 #2: ffff888038411140 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline] #2: ffff888038411140 (&dev->mutex){....}-{4:4}, at: nfc_dev_up+0x3f/0x350 net/nfc/core.c:95 #3: ffff8880b1f50348 (&ndev->req_lock){+.+.}-{4:4}, at: nci_open_device net/nfc/nci/core.c:478 [inline] #3: ffff8880b1f50348 (&ndev->req_lock){+.+.}-{4:4}, at: nci_dev_up+0xa3/0xdd0 net/nfc/nci/core.c:643 2 locks held by syz.2.5350/27279: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.2.5350/27284: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.2.5350/27289: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.3.5352/27286: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.3.5352/27287: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.4.5354/27297: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.0.5360/27311: #0: ffffffff8fe3ddc8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe3dc00 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 2 locks held by syz.0.5360/27312: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 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: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+0xfaa/0x1000 kernel/hung_task.c:515 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: 27289 Comm: syz.2.5350 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x5c/0x70 kernel/kcov.c:235 Code: a8 16 00 00 83 fa 02 75 21 48 8b 91 b0 16 00 00 48 8b 32 48 8d 7e 01 8b 89 ac 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 8f a9 f0 09 cc 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 RSP: 0018:ffffc9000e0ff310 EFLAGS: 00000293 RAX: ffffffff823d7cf3 RBX: 0000000000000001 RCX: ffff888061221ec0 RDX: 0000000000000000 RSI: 000000000008d4dd RDI: 0000000400000000 RBP: ffffc9000e0ff670 R08: ffffea0002353747 R09: 1ffffd400046a6e8 R10: dffffc0000000000 R11: fffff9400046a6e9 R12: dffffc0000000000 R13: dffffc0000000000 R14: 000000000008d4dd R15: 000000000008d4dd FS: 0000000000000000(0000) GS:ffff888125345000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4b34be7158 CR3: 0000000077206000 CR4: 00000000003526f0 Call Trace: __nr_to_section include/linux/mmzone.h:1972 [inline] __pfn_to_section include/linux/mmzone.h:2114 [inline] pfn_valid+0x463/0x480 include/linux/mmzone.h:2196 page_table_check_clear+0x21/0x5f0 mm/page_table_check.c:70 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:846 [inline] zap_present_folio_ptes mm/memory.c:1643 [inline] zap_present_ptes mm/memory.c:1725 [inline] do_zap_pte_range mm/memory.c:1827 [inline] zap_pte_range mm/memory.c:1929 [inline] zap_pmd_range mm/memory.c:2021 [inline] zap_pud_range mm/memory.c:2049 [inline] zap_p4d_range mm/memory.c:2070 [inline] unmap_page_range+0x33b3/0x48f0 mm/memory.c:2091 unmap_single_vma mm/memory.c:2133 [inline] unmap_vmas+0x48f/0x6a0 mm/memory.c:2171 exit_mmap+0x280/0x9e0 mm/mmap.c:1302 __mmput+0x118/0x430 kernel/fork.c:1177 exit_mm+0x18e/0x250 kernel/exit.c:581 do_exit+0x6a2/0x23c0 kernel/exit.c:965 do_group_exit+0x21b/0x2d0 kernel/exit.c:1119 get_signal+0x1284/0x1330 kernel/signal.c:3039 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:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f63f815d04e Code: Unable to access opcode bytes at 0x7f63f815d024. RSP: 002b:00007f63f8fc4e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: 0000000000000020 RBX: 00007f63f8fc66c0 RCX: 00007f63f815d04e RDX: 0000000000000020 RSI: 00007f63f8fc5000 RDI: 0000000000000006 RBP: 0000000000000000 R08: 00007f63f8fc4f04 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006 R13: 00007f63f8fc4f58 R14: 00007f63f8fc5000 R15: 0000000000000000 GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog