INFO: task udevd:5230 blocked for more than 143 seconds. Not tainted 6.11.0-rc4-syzkaller-00139-g4186c8d9e6af #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:20952 pid:5230 tgid:5230 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 wait_for_reconnect drivers/block/nbd.c:1023 [inline] nbd_handle_cmd drivers/block/nbd.c:1065 [inline] nbd_queue_rq+0x7cd/0x2f70 drivers/block/nbd.c:1123 blk_mq_dispatch_rq_list+0xb89/0x1b30 block/blk-mq.c:2032 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline] __blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309 blk_mq_sched_dispatch_requests+0xcb/0x140 block/blk-mq-sched.c:331 blk_mq_run_hw_queue+0x576/0xae0 block/blk-mq.c:2245 blk_mq_flush_plug_list+0x1115/0x1880 block/blk-mq.c:2794 __blk_flush_plug+0x420/0x500 block/blk-core.c:1198 blk_finish_plug block/blk-core.c:1225 [inline] __submit_bio+0x422/0x560 block/blk-core.c:623 __submit_bio_noacct_mq block/blk-core.c:696 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:725 submit_bh fs/buffer.c:2829 [inline] block_read_full_folio+0x93b/0xcd0 fs/buffer.c:2456 filemap_read_folio+0x1a0/0x790 mm/filemap.c:2355 do_read_cache_folio+0x134/0x820 mm/filemap.c:3789 read_mapping_folio include/linux/pagemap.h:913 [inline] read_part_sector+0xb3/0x330 block/partitions/core.c:712 adfspart_check_ICS+0xd9/0x9a0 block/partitions/acorn.c:360 check_partition block/partitions/core.c:138 [inline] blk_add_partitions block/partitions/core.c:579 [inline] bdev_disk_changed+0x72c/0x13d0 block/partitions/core.c:683 blkdev_get_whole+0x2d2/0x450 block/bdev.c:700 bdev_open+0x2d4/0xc60 block/bdev.c:909 blkdev_open+0x3e8/0x570 block/fops.c:630 do_dentry_open+0x970/0x1440 fs/open.c:959 vfs_open+0x3e/0x330 fs/open.c:1089 do_open fs/namei.c:3727 [inline] path_openat+0x2b3e/0x3470 fs/namei.c:3886 do_filp_open+0x235/0x490 fs/namei.c:3913 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416 do_sys_open fs/open.c:1431 [inline] __do_sys_openat fs/open.c:1447 [inline] __se_sys_openat fs/open.c:1442 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1442 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1e145169a4 RSP: 002b:00007fffa64727e0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000562446448e10 RCX: 00007f1e145169a4 RDX: 00000000000a0800 RSI: 0000562446441f10 RDI: 00000000ffffff9c RBP: 0000562446441f10 R08: 0000000000000001 R09: 7fffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800 R13: 00005624464396f0 R14: 0000000000000001 R15: 0000562446427910 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #0: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6626 3 locks held by kworker/u8:5/66: #0: ffff888015889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] #0: ffff888015889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 #1: ffffc900020bfd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] #1: ffffc900020bfd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 #2: ffffffff8fc845c8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 2 locks held by kworker/u8:7/2581: 2 locks held by getty/4985: #0: ffff88802ffd80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ac/0x1e00 drivers/tty/n_tty.c:2211 3 locks held by udevd/5230: #0: ffff8880211454c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open+0xf0/0xc60 block/bdev.c:897 #1: ffff888020b4ee90 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline] #1: ffff888020b4ee90 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline] #1: ffff888020b4ee90 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x54d/0xae0 block/blk-mq.c:2245 #2: ffff888021228180 (&cmd->lock){+.+.}-{3:3}, at: nbd_queue_rq+0xfc/0x2f70 drivers/block/nbd.c:1115 3 locks held by udevd/5236: #0: ffff8880212014c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open+0xf0/0xc60 block/bdev.c:897 #1: ffff888020b85710 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline] #1: ffff888020b85710 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline] #1: ffff888020b85710 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x54d/0xae0 block/blk-mq.c:2245 #2: ffff8880212f8180 (&cmd->lock){+.+.}-{3:3}, at: nbd_queue_rq+0xfc/0x2f70 drivers/block/nbd.c:1115 3 locks held by udevd/5239: #0: ffff8880212d94c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open+0xf0/0xc60 block/bdev.c:897 #1: ffff888020bba110 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline] #1: ffff888020bba110 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline] #1: ffff888020bba110 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x54d/0xae0 block/blk-mq.c:2245 #2: ffff888021368180 (&cmd->lock){+.+.}-{3:3}, at: nbd_queue_rq+0xfc/0x2f70 drivers/block/nbd.c:1115 3 locks held by udevd/5241: #0: ffff8880212054c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open+0xf0/0xc60 block/bdev.c:897 #1: ffff888020b85c10 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline] #1: ffff888020b85c10 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline] #1: ffff888020b85c10 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x54d/0xae0 block/blk-mq.c:2245 #2: ffff888021330180 (&cmd->lock){+.+.}-{3:3}, at: nbd_queue_rq+0xfc/0x2f70 drivers/block/nbd.c:1115 3 locks held by udevd/7066: #0: ffff888020db74c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open+0xf0/0xc60 block/bdev.c:897 #1: ffff888020870090 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline] #1: ffff888020870090 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline] #1: ffff888020870090 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x54d/0xae0 block/blk-mq.c:2245 #2: ffff888021290180 (&cmd->lock){+.+.}-{3:3}, at: nbd_queue_rq+0xfc/0x2f70 drivers/block/nbd.c:1115 2 locks held by syz.1.1507/9675: #0: ffffffff8fc845c8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8fc845c8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3e/0x1b0 drivers/net/tun.c:3510 #1: ffffffff8e93d6f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:296 [inline] #1: ffffffff8e93d6f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:958 1 lock held by syz.4.1510/9686: #0: ffffffff8fc845c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fc845c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6644 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-rc4-syzkaller-00139-g4186c8d9e6af #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xff4/0x1040 kernel/hung_task.c:379 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111