INFO: task udevd:4373 blocked for more than 145 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:23584 pid:4373 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 io_schedule+0x7c/0xd0 kernel/sched/core.c:8798 folio_wait_bit_common+0x6e1/0xf60 mm/filemap.c:1324 folio_put_wait_locked mm/filemap.c:1493 [inline] do_read_cache_folio+0x1a9/0x760 mm/filemap.c:3641 read_mapping_folio include/linux/pagemap.h:799 [inline] read_part_sector+0xce/0x350 block/partitions/core.c:724 adfspart_check_POWERTEC+0xb4/0x870 block/partitions/acorn.c:454 check_partition block/partitions/core.c:146 [inline] blk_add_partitions block/partitions/core.c:609 [inline] bdev_disk_changed+0x7bd/0x1480 block/partitions/core.c:695 blkdev_get_whole+0x2e8/0x370 block/bdev.c:704 blkdev_get_by_dev+0x32e/0xa60 block/bdev.c:841 blkdev_open+0x11e/0x2e0 block/fops.c:500 do_dentry_open+0x7e9/0x10d0 fs/open.c:882 do_open fs/namei.c:3634 [inline] path_openat+0x25c6/0x2e70 fs/namei.c:3791 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818 do_sys_openat2+0x142/0x490 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa97b6a7407 RSP: 002b:00007ffd89d408e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa97bd55880 RCX: 00007fa97b6a7407 RDX: 00000000000a0800 RSI: 00005582ec1c1a10 RDI: ffffffffffffff9c RBP: 00005582ec1a1910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00005582ec1b6830 R13: 00005582ec1b9410 R14: 0000000000000000 R15: 00005582ec1b6830 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8c92bb70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8c92c390 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8c92b1e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8c92b1e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8c92b1e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 2 locks held by getty/4029: #0: ffff88814cf61098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198 2 locks held by kworker/u4:6/4349: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90004a7fd00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 1 lock held by udevd/4373: #0: ffff888142fe74c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832 2 locks held by kworker/u4:7/4384: 1 lock held by syz-executor/6447: 3 locks held by kworker/u4:23/7980: 1 lock held by syz-executor/11059: #0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:546 2 locks held by syz.3.1937/13794: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 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+0x168/0x22e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 13794 Comm: syz.3.1937 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:memory_is_nonzero mm/kasan/generic.c:101 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline] RIP: 0010:kasan_check_range+0x5c/0x290 mm/kasan/generic.c:189 Code: 01 00 00 00 00 fc ff df 49 89 fb 49 c1 eb 03 49 b8 00 00 00 00 00 fc ff df 4f 8d 0c 03 48 8d 5c 37 ff 48 c1 eb 03 4e 8d 14 3b <4d> 89 d6 4d 29 ce 49 83 fe 10 7f 26 4d 85 f6 0f 84 39 01 00 00 48 RSP: 0018:ffffc900036d68a0 EFLAGS: 00000807 RAX: 0000000000000001 RBX: 1ffffffff2119648 RCX: ffffffff8163e244 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff908cb240 RBP: 0000000000000009 R08: dffffc0000000000 R09: fffffbfff2119648 R10: fffffbfff2119649 R11: 1ffffffff2119648 R12: 0000000000000200 R13: dffffc0000000000 R14: ffff888019778b58 R15: dffffc0000000001 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f45d03b9358 CR3: 000000007b28d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:72 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] hlock_class kernel/locking/lockdep.c:228 [inline] mark_lock+0x94/0x320 kernel/locking/lockdep.c:4606 mark_usage kernel/locking/lockdep.c:4549 [inline] __lock_acquire+0xd6f/0x7c50 kernel/locking/lockdep.c:5003 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline] percpu_ref_tryget+0x31/0x180 include/linux/percpu-refcount.h:266 css_tryget include/linux/cgroup.h:357 [inline] get_mem_cgroup_from_mm+0xfe/0x290 mm/memcontrol.c:1041 __mem_cgroup_charge+0x11/0x80 mm/memcontrol.c:6943 mem_cgroup_charge include/linux/memcontrol.h:672 [inline] __filemap_add_folio+0xc9e/0x18d0 mm/filemap.c:854 filemap_add_folio+0xaa/0x3c0 mm/filemap.c:962 __filemap_get_folio+0x74c/0xdd0 mm/filemap.c:2004 pagecache_get_page+0x26/0x250 mm/folio-compat.c:110 simple_write_begin+0x27/0xd0 fs/libfs.c:561 generic_perform_write+0x2f7/0x5a0 mm/filemap.c:3862 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989 __kernel_write_iter+0x26d/0x630 fs/read_write.c:517 dump_emit_page fs/coredump.c:950 [inline] dump_user_range+0x3ea/0x7f0 fs/coredump.c:977 elf_core_dump+0x2f77/0x3490 fs/binfmt_elf.c:2354 do_coredump+0x15ff/0x22b0 fs/coredump.c:824 get_signal+0x10aa/0x1350 kernel/signal.c:2857 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1490 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7f0549c4f6b7 Code: 88 15 42 60 ec 00 88 05 3f 60 ec 00 c3 50 48 8d 35 e9 48 1c 00 48 8d 3d ef 48 1c 00 31 c0 e8 20 f7 ff ff 53 89 fb 48 83 ec 10 <64> 8b 04 25 94 ff ff ff 85 c0 74 2a 89 fe 31 c0 bf 3c 00 00 00 e8 RSP: 002b:00007f0547fd7120 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f0549d8f749 RDX: 00007f0547fd7140 RSI: 00007f0547fd7270 RDI: 000000000000000b RBP: 00007f0549e13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f0549fe6038 R14: 00007f0549fe5fa0 R15: 00007ffd655e5738