INFO: task udevd:4199 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:23392 pid: 4199 ppid: 3561 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 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+0x815/0xe00 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+0xb05/0x1030 mm/filemap.c:3480 read_mapping_page include/linux/pagemap.h:515 [inline] read_part_sector+0xd4/0x4f0 block/partitions/core.c:726 adfspart_check_ICS+0xbf/0xe00 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+0x917/0x16b0 block/partitions/core.c:697 blkdev_get_whole+0x2f9/0x390 block/bdev.c:682 blkdev_get_by_dev+0x2d0/0xa60 block/bdev.c:827 blkdev_open+0x12d/0x2c0 block/fops.c:466 do_dentry_open+0x7ff/0xf80 fs/open.c:826 do_open fs/namei.c:3616 [inline] path_openat+0x2682/0x2f30 fs/namei.c:3750 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777 do_sys_openat2+0x142/0x4a0 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: 0033:0x7efcec332407 RSP: 002b:00007ffc7c5630a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007efcec244880 RCX: 00007efcec332407 RDX: 00000000000a0800 RSI: 000055a3bf81d480 RDI: ffffffffffffff9c RBP: 000055a3bf81c910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055a3bf82eb20 R13: 000055a3bf834410 R14: 0000000000000000 R15: 000055a3bf82eb20 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by udevd/3561: 2 locks held by getty/3942: #0: ffff88802b95f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900026562e8 ( &ldata->atomic_read_lock ){+.+.}-{3:3} , at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158 1 lock held by udevd/4199: #0: ffff88801fd0a118 ( &disk->open_mutex ){+.+.}-{3:3} , at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820 3 locks held by kworker/1:10/4447: #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90003a47d00 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #2: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845 9 locks held by kworker/1:13/4451: 2 locks held by kworker/1:14/4452: #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90003b57d00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 1 lock held by syz.3.188/5551: #0: ffff88801fd0a118 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1ab/0x320 block/bdev.c:1053 1 lock held by syz-executor/5876: #0: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #0: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845 4 locks held by udevd/6520: #0: ffff888023b98418 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182 #1: ffffe8ffffd9ebc8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x14a/0x810 kernel/sched/psi.c:857 #2: ffffffff8c1ece20 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: __fs_reclaim_acquire mm/page_alloc.c:4580 [inline] #2: ffffffff8c1ece20 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4594 #3: ffff888140094688 (&memcg->move_lock){..-.}-{2:2}, at: lock_page_memcg+0x1a7/0x410 mm/memcontrol.c:2058 2 locks held by syz-executor/7134: #0: ffff88801f6b6118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915 #1: ffff888147aee468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366 1 lock held by dhcpcd-run-hook/8759: ============================================= 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 10/25/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 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+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 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: 8763 Comm: dhcpcd-run-hook Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:174 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x2c/0x60 kernel/kcov.c:206 Code: 04 24 65 48 8b 0d a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c <8b> 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 RSP: 0018:ffffc90002ebf9b8 EFLAGS: 00000246 RAX: ffffffff81a12d0e RBX: ffffea0002fff608 RCX: ffff88802b0e8000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90002ebfac8 R08: dffffc0000000000 R09: fffff940003fce37 R10: fffff940003fce37 R11: 1ffffd40003fce36 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffea0001fe71c0 R15: ffffc90002ebfa40 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffca2ba0038 CR3: 000000000be8e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: _compound_head include/linux/page-flags.h:198 [inline] release_pages+0x1be/0x1bb0 mm/swap.c:907 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:240 [inline] tlb_flush_mmu mm/mmu_gather.c:247 [inline] tlb_finish_mmu+0x164/0x2e0 mm/mmu_gather.c:338 exit_mmap+0x3a6/0x5f0 mm/mmap.c:3218 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x5a1/0x20a0 kernel/exit.c:870 do_group_exit+0x12e/0x300 kernel/exit.c:997 __do_sys_exit_group kernel/exit.c:1008 [inline] __se_sys_exit_group kernel/exit.c:1006 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1006 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: 0033:0x7fa20ec296c5 Code: Unable to access opcode bytes at RIP 0x7fa20ec2969b. RSP: 002b:00007ffca2b9ff48 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ffca2ba0204 RCX: 00007fa20ec296c5 RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000 RBP: 0000000000000003 R08: 00007ffca2ba0040 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffca2ba0280 R14: 00007fa20ee31000 R15: 00005558023b4d98