INFO: task syz.4.509:7996 blocked for more than 143 seconds. Not tainted 6.15.0-syzkaller-10769-g7d4e49a77d99 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.509 state:D stack:26584 pid:7996 tgid:7994 ppid:5807 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6874 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6931 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:747 bdev_release+0x15a/0x6d0 block/bdev.c:1128 blkdev_release+0x15/0x20 block/fops.c:684 __fput+0x402/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:114 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f52a198e969 RSP: 002b:00007f52a2881038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007f52a1bb5fa0 RCX: 00007f52a198e969 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007f52a1a10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f52a1bb5fa0 R15: 00007fff34a25f68 Showing all locks held in the system: 2 locks held by kworker/u8:0/12: #0: ffff8881466e6148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90000117d10 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 1 lock held by khungtaskd/31: #0: ffffffff8e5c4d80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c4d80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c4d80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770 2 locks held by getty/5569: #0: ffff88803269f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 1 lock held by udevd/5828: #0: ffff8880b843bc58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:614 [inline] #0: ffff8880b843bc58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:599 3 locks held by kworker/1:6/5863: #0: ffff88801eef3148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000481fd10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffff888029b39198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline] #2: ffff888029b39198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1c0/0x4fa0 drivers/usb/core/hub.c:5859 1 lock held by udevd/7362: #0: ffff8880269fe358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945 1 lock held by syz.4.509/7996: #0: ffff8880269fe358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x15a/0x6d0 block/bdev.c:1128 5 locks held by syz-executor/9746: 2 locks held by syz.3.874/9916: #0: ffffffff8e492ac8 (sched_core_mutex){+.+.}-{4:4}, at: sched_core_get+0x3f/0xa0 kernel/sched/core.c:452 #1: ffffffff8e5d0338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 1 lock held by syz.0.875/9920: #0: ffffffff8e492ac8 (sched_core_mutex){+.+.}-{4:4}, at: sched_core_get+0x3f/0xa0 kernel/sched/core.c:452 3 locks held by sed/9937: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-syzkaller-10769-g7d4e49a77d99 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:470 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9943 Comm: dhcpcd-run-hook Not tainted 6.15.0-syzkaller-10769-g7d4e49a77d99 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:121 [inline] RIP: 0010:lock_acquire kernel/locking/lockdep.c:5847 [inline] RIP: 0010:lock_acquire+0x10a/0x350 kernel/locking/lockdep.c:5828 Code: 85 4f ff ff ff e8 76 fb 93 ff e9 45 ff ff ff 48 8b 74 24 68 48 89 df e8 a4 51 8a 00 8b 0d 42 7b 0f 0f 85 c9 0f 84 b1 00 00 00 <65> 8b 05 77 87 33 12 85 c0 0f 85 a2 00 00 00 65 48 8b 05 f7 45 33 RSP: 0018:ffffc90003caf570 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff8e5c4d80 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff816ab8c1 RDI: fffffbfff1cb89b0 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000007c40 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124865000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcc84b63e8 CR3: 000000005aa97000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 00000000000000a8 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548 slab_free_hook mm/slub.c:2341 [inline] slab_free mm/slub.c:4642 [inline] kmem_cache_free+0x15a/0x4d0 mm/slub.c:4744 anon_vma_free mm/rmap.c:137 [inline] __put_anon_vma+0x114/0x3a0 mm/rmap.c:2756 put_anon_vma include/linux/rmap.h:117 [inline] unlink_anon_vmas+0x58a/0x820 mm/rmap.c:444 free_pgtables+0x2d4/0x810 mm/memory.c:400 exit_mmap+0x3fb/0xb90 mm/mmap.c:1295 __mmput+0x12a/0x410 kernel/fork.c:1121 mmput+0x62/0x70 kernel/fork.c:1144 exit_mm kernel/exit.c:581 [inline] do_exit+0x7bc/0x2bd0 kernel/exit.c:943 do_group_exit+0xd3/0x2a0 kernel/exit.c:1104 __do_sys_exit_group kernel/exit.c:1115 [inline] __se_sys_exit_group kernel/exit.c:1113 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1113 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa662d3a6c5 Code: Unable to access opcode bytes at 0x7fa662d3a69b. RSP: 002b:00007ffcc84b62f8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ffcc84b6604 RCX: 00007fa662d3a6c5 RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000 RBP: 0000000000000003 R08: 00007ffcc84b63f0 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffcc84b6630 R14: 00007fa662f4a000 R15: 0000564dd68f2d98