INFO: task udevd:5765 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:23176 pid:5765 ppid:5141 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 io_schedule+0x80/0xd0 kernel/sched/core.c:9024 folio_wait_bit_common+0x881/0xfa0 mm/filemap.c:1329 folio_put_wait_locked mm/filemap.c:1493 [inline] do_read_cache_folio+0x1c0/0x7f0 mm/filemap.c:3791 read_mapping_folio include/linux/pagemap.h:898 [inline] read_part_sector+0xd2/0x350 block/partitions/core.c:718 adfspart_check_POWERTEC+0x93/0xed0 block/partitions/acorn.c:454 check_partition block/partitions/core.c:138 [inline] blk_add_partitions block/partitions/core.c:600 [inline] bdev_disk_changed+0x755/0x1450 block/partitions/core.c:689 blkdev_get_whole+0x30d/0x390 block/bdev.c:668 blkdev_get_by_dev+0x3a9/0x610 block/bdev.c:810 blkdev_open+0x14e/0x360 block/fops.c:589 do_dentry_open+0x880/0x14b0 fs/open.c:929 do_open fs/namei.c:3683 [inline] path_openat+0x284f/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f7cb52a7407 RSP: 002b:00007ffc4d18a880 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f7cb5977880 RCX: 00007f7cb52a7407 RDX: 00000000000a0800 RSI: 000055ce2fc69340 RDI: ffffffffffffff9c RBP: 000055ce2fc4c910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055ce2fc6e040 R13: 000055ce2fc64410 R14: 0000000000000000 R15: 000055ce2fc6e040 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/14: #0: ffffffff8d132750 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0xb11/0xdf0 kernel/rcu/tasks.h:607 1 lock held by khungtaskd/29: #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by kworker/u4:3/49: 3 locks held by udevd/5141: 2 locks held by getty/5530: #0: ffff88814ccb50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217 1 lock held by udevd/5765: #0: ffff888021eba4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x11b/0x610 block/bdev.c:801 2 locks held by kworker/u4:2/21836: 2 locks held by syz.1.6235/25373: 1 lock held by syz.3.6239/25376: #0: ffffffff8d137640 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4089 1 lock held by syz.3.6239/25380: #0: ffffffff8d137640 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4089 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf59/0xfa0 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2946 Comm: kworker/u4:8 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_nc_worker RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x36/0x60 kernel/kcov.c:216 Code: 10 46 7c 7e 65 8b 15 11 46 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 24 16 00 00 00 74 2c 8b 91 00 16 00 00 <83> fa 02 75 21 48 8b 91 08 16 00 00 48 8b 32 48 8d 7e 01 8b 89 04 RSP: 0018:ffffc9000bb37b58 EFLAGS: 00000246 RAX: ffffffff8a566aab RBX: 0000000000000001 RCX: ffff88802bd55a00 RDX: 0000000000000000 RSI: ffffffff8b1d32c0 RDI: ffffffff8b1d3280 RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff223daa0 R10: dffffc0000000000 R11: fffffbfff223daa1 R12: dffffc0000000000 R13: ffffffff8a566972 R14: ffff88805ea98d00 R15: 0000000000000105 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000000cf32000 CR4: 00000000003526f0 Call Trace: rcu_read_unlock include/linux/rcupdate.h:815 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0x20b/0x600 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293