INFO: task udevd:4546 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:23344 pid: 4546 ppid: 3558 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503 wait_on_page_bit_common+0x8bf/0xeb0 mm/filemap.c:1356 wait_on_page_bit mm/filemap.c:1417 [inline] wait_on_page_locked include/linux/pagemap.h:688 [inline] wait_on_page_read mm/filemap.c:3437 [inline] do_read_cache_page+0xae6/0x1010 mm/filemap.c:3480 read_mapping_page include/linux/pagemap.h:515 [inline] read_part_sector+0xd7/0x4c0 block/partitions/core.c:726 adfspart_check_ICS+0xc3/0xe90 block/partitions/acorn.c:360 check_partition block/partitions/core.c:148 [inline] blk_add_partitions block/partitions/core.c:611 [inline] bdev_disk_changed+0x936/0x1690 block/partitions/core.c:697 blkdev_get_whole+0x2f9/0x390 block/bdev.c:678 blkdev_get_by_dev+0x2da/0xa50 block/bdev.c:823 blkdev_open+0x128/0x2c0 block/fops.c:466 do_dentry_open+0x7f7/0xf90 fs/open.c:826 do_open fs/namei.c:3659 [inline] path_openat+0x2718/0x2fb0 fs/namei.c:3793 do_filp_open+0x1df/0x400 fs/namei.c:3820 do_sys_openat2+0x14b/0x500 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fef89ca6407 RSP: 002b:00007ffca9dabaf0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fef89bb8880 RCX: 00007fef89ca6407 RDX: 00000000000a0800 RSI: 00005599763722b0 RDI: ffffffffffffff9c RBP: 000055997633a910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055997634de20 R13: 0000559976352410 R14: 0000000000000000 R15: 000055997634de20 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 4 locks held by kworker/u4:1/144: #0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc900010afd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffffffff8d441610 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589 #3: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #3: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845 3 locks held by kworker/u4:3/156: 2 locks held by getty/3941: #0: ffff88802c4a5098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158 2 locks held by syz-executor/4173: #0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: vtime_task_switch include/linux/vtime.h:101 [inline] #0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: finish_task_switch+0x3c6/0x650 kernel/sched/core.c:4917 #1: ffff8880b9127888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: spin_lock_bh include/linux/spinlock.h:369 [inline] #1: ffff8880b9127888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: lock_sock_nested+0x68/0x100 net/core/sock.c:3261 1 lock held by syz-executor/4190: #0: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #0: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845 3 locks held by kworker/1:4/4227: #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc900034afd00 (fqdir_free_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffffffff8c3238f0 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043 1 lock held by udevd/4546: #0: ffff888020d70518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x162/0xa50 block/bdev.c:816 3 locks held by kworker/1:17/5962: 2 locks held by kworker/1:18/5963: #0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc90003837d00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe1b/0xe60 kernel/hung_task.c:369 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9 Comm: kworker/u4:0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline] RIP: 0010:write_comp_data kernel/kcov.c:226 [inline] RIP: 0010:__sanitizer_cov_trace_switch+0x85/0xe0 kernel/kcov.c:328 Code: 77 4e 8b 54 ce 10 65 44 8b 1d 5f 56 89 7e 41 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 41 83 b8 34 16 00 00 00 74 cf <45> 8b 98 10 16 00 00 41 83 fb 03 75 c2 4d 8b 98 18 16 00 00 45 8b RSP: 0018:ffffc90000ce7698 EFLAGS: 00000246 RAX: 0000000000000020 RBX: 00000047c6c0715a RCX: 0000000000000005 RDX: ffffffff817c064d RSI: ffffffff8c3605a0 RDI: 000000000000000a RBP: 000000000000000a R08: ffff88813fe90000 R09: 0000000000000011 R10: 0000000000000011 R11: 0000000000000000 R12: ffff88805702e0e0 R13: dffffc0000000000 R14: 00000000000000d0 R15: 00000000000186aa FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f08cbd57c38 CR3: 000000006238e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: check_buffer+0x23d/0x880 kernel/trace/ring_buffer.c:3452 __rb_reserve_next+0x4d9/0xd00 kernel/trace/ring_buffer.c:3581 rb_reserve_next_event kernel/trace/ring_buffer.c:3716 [inline] ring_buffer_lock_reserve+0xadd/0xed0 kernel/trace/ring_buffer.c:3775 __trace_buffer_lock_reserve kernel/trace/trace.c:942 [inline] trace_event_buffer_lock_reserve+0xd4/0x6a0 kernel/trace/trace.c:2819 trace_event_buffer_reserve+0x2a8/0x3d0 kernel/trace/trace_events.c:627 trace_event_raw_event_lock_acquire+0x158/0x2b0 include/trace/events/lock.h:13 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x3d7/0x400 kernel/locking/lockdep.c:5596 process_one_work+0x7ba/0xff0 kernel/workqueue.c:2286 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287