INFO: task syz.5.1205:9032 blocked for more than 143 seconds. Not tainted 6.1.133-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.1205 state:D stack:26624 pid:9032 ppid:4634 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6561 schedule+0xbf/0x180 kernel/sched/core.c:6637 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 blkdev_put+0x100/0x750 block/bdev.c:913 blkdev_close+0x56/0x80 block/fops.c:514 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 get_signal+0x15d0/0x17a0 kernel/signal.c:2648 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8786f8d169 RSP: 002b:00007f8786dde038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007f87871a6080 RCX: 00007f8786f8d169 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007f878700e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f87871a6080 R15: 00007fffd36097c8 Showing all locks held in the system: 2 locks held by kworker/u4:0/9: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d32e910 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8d32f110 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 2 locks held by kworker/1:0/22: 1 lock held by khungtaskd/28: #0: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510 1 lock held by udevd/3623: 2 locks held by getty/4006: #0: ffff88803195b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x54a/0x1620 drivers/tty/n_tty.c:2198 1 lock held by syz-executor/4263: 1 lock held by udevd/8009: #0: ffff888026b584c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x148/0xa10 block/bdev.c:815 1 lock held by syz.5.1205/9032: #0: ffff888026b584c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x100/0x750 block/bdev.c:913 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.133-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1ca/0x430 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+0xf88/0xfd0 kernel/hung_task.c:377 kthread+0x28d/0x320 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: 9427 Comm: kworker/u4:14 Not tainted 6.1.133-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:__preempt_count_add kernel/rcu/tree.c:717 [inline] RIP: 0010:rcu_is_watching+0x2/0xb0 kernel/rcu/tree.c:720 Code: 44 24 21 02 0f 84 02 ff ff ff e9 6c ff ff ff 48 c7 c7 e0 50 33 8d 4c 89 f6 e8 ea 7c fb 02 e9 2b ff ff ff e8 30 fd 3d 09 41 57 <41> 56 53 65 ff 05 1c d8 8e 7e e8 6f 15 3e 09 89 c3 83 f8 08 73 76 RSP: 0018:ffffc9000e3a7870 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff816ab57b RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ea0bba8 RBP: ffffc9000e3a79c8 R08: dffffc0000000000 R09: fffffbfff1d41776 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92001c74f18 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f496d379178 CR3: 000000000d08e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xfa/0x5a0 kernel/locking/lockdep.c:5633 local_lock_acquire include/linux/local_lock_internal.h:29 [inline] ___slab_alloc+0x226/0x1270 mm/slub.c:3099 __slab_alloc mm/slub.c:3279 [inline] slab_alloc_node mm/slub.c:3364 [inline] __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc_node_track_caller+0xa0/0x220 mm/slab_common.c:956 kmalloc_reserve net/core/skbuff.c:446 [inline] __alloc_skb+0x12a/0x2c0 net/core/skbuff.c:515 alloc_skb include/linux/skbuff.h:1271 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x24c/0xab0 drivers/net/netdevsim/dev.c:851 process_one_work+0x917/0x1260 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295