INFO: task syz.1.3632:20372 blocked for more than 143 seconds. Not tainted 6.14.0-rc5-syzkaller-00234-gb7c90e3e717a #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.3632 state:D stack:22176 pid:20372 tgid:20372 ppid:12589 task_flags:0x400040 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914 __mutex_lock_common kernel/locking/mutex.c:662 [inline] __mutex_lock+0x817/0x1010 kernel/locking/mutex.c:730 bdev_release+0x17e/0x700 block/bdev.c:1086 blkdev_release+0x15/0x20 block/fops.c:660 __fput+0x3e9/0x9f0 fs/file_table.c:464 task_work_run+0x24f/0x310 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3eaed8d169 RSP: 002b:00007ffdd7dec658 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f3eaefa7ba0 RCX: 00007f3eaed8d169 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f3eaefa7ba0 R08: 000000000000176c R09: 0000001cd7dec94f R10: 00007f3eaefa7ac0 R11: 0000000000000246 R12: 000000000017814d R13: 00007ffdd7dec750 R14: ffffffffffffffff R15: 00007ffdd7dec770 INFO: task syz.1.3632:20376 blocked for more than 145 seconds. Not tainted 6.14.0-rc5-syzkaller-00234-gb7c90e3e717a #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.3632 state:D stack:26288 pid:20376 tgid:20372 ppid:12589 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914 __mutex_lock_common kernel/locking/mutex.c:662 [inline] __mutex_lock+0x817/0x1010 kernel/locking/mutex.c:730 bdev_release+0x17e/0x700 block/bdev.c:1086 blkdev_release+0x15/0x20 block/fops.c:660 __fput+0x3e9/0x9f0 fs/file_table.c:464 task_work_run+0x24f/0x310 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3eaed8d169 RSP: 002b:00007f3eafb52038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007f3eaefa6160 RCX: 00007f3eaed8d169 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 000000000000000d RBP: 00007f3eaee0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f3eaefa6160 R15: 00007ffdd7dec4f8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8eb39360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8eb39360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8eb39360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746 3 locks held by kworker/u8:7/3002: 2 locks held by getty/5573: #0: ffff88803120d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x616/0x1770 drivers/tty/n_tty.c:2211 2 locks held by kworker/u8:8/5917: 1 lock held by udevd/20063: #0: ffff888025d284c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xf0/0xc50 block/bdev.c:903 1 lock held by syz.1.3632/20372: #0: ffff888025d284c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x17e/0x700 block/bdev.c:1086 1 lock held by syz.1.3632/20376: #0: ffff888025d284c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x17e/0x700 block/bdev.c:1086 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-rc5-syzkaller-00234-gb7c90e3e717a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline] watchdog+0x1058/0x10a0 kernel/hung_task.c:399 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 3002 Comm: kworker/u8:7 Not tainted 6.14.0-rc5-syzkaller-00234-gb7c90e3e717a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: iou_exit io_ring_exit_work RIP: 0010:preempt_count_add+0x5c/0x190 kernel/sched/core.c:5860 Code: 18 00 75 07 65 8b 05 9b 53 74 7e 65 01 1d 94 53 74 7e 48 c7 c0 80 b9 61 9a 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 e4 00 00 00 <83> 3d ed 37 d2 18 00 75 11 65 8b 05 6c 53 74 7e 0f b6 c0 3d f5 00 RSP: 0018:ffffc9000be77310 EFLAGS: 00000297 RAX: 0000000000000004 RBX: 0000000000000001 RCX: ffffffff9a61b903 RDX: dffffc0000000000 RSI: ffffffff82268bda RDI: 0000000000000001 RBP: ffffc9000be77438 R08: 0000000000000001 R09: ffffc9000be774f0 R10: ffffc9000be77450 R11: ffffffff81ad6ae0 R12: dffffc0000000000 R13: ffffc9000be77400 R14: ffffffff82268bda R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb277178ab8 CR3: 00000000429f8000 CR4: 00000000003526f0 DR0: 0000000000000002 DR1: fffffffffffffffb DR2: 0000000000010001 DR3: 0000000000000004 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame+0xb0/0x22d0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xaa/0xc0 mm/kasan/generic.c:548 __call_rcu_common kernel/rcu/tree.c:3065 [inline] call_rcu+0x168/0xac0 kernel/rcu/tree.c:3172 slab_free_hook mm/slub.c:2317 [inline] slab_free mm/slub.c:4609 [inline] kmem_cache_free+0x30e/0x410 mm/slub.c:4711 io_req_caches_free+0xa7/0x120 io_uring/io_uring.c:2690 io_ring_exit_work+0x382/0x8a0 io_uring/io_uring.c:2889 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd30 kernel/workqueue.c:3400 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 vkms_vblank_simulate: vblank timer overrun