INFO: task syz.1.824:9066 blocked for more than 159 seconds. Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.824 state:D stack:23808 pid:9066 tgid:9066 ppid:8408 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 __schedule_loop kernel/sched/core.c:6759 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6774 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6831 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752 pipe_release+0x48/0x320 fs/pipe.c:727 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:228 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:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4cac77dff9 RSP: 002b:00007fff14926c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f4cac937a80 RCX: 00007f4cac77dff9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f4cac937a80 R08: 0000000000000006 R09: 00007fff14926f6f R10: 00000000003ffc8c R11: 0000000000000246 R12: 000000000007e015 R13: 00007fff14926d80 R14: 0000000000000032 R15: ffffffffffffffff Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720 2 locks held by udevd/4689: 2 locks held by getty/4994: #0: ffff88814c1bb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 1 lock held by sshd/5219: 3 locks held by syz-executor/8407: 1 lock held by syz.1.824/9066: #0: ffff88802ca65468 (&pipe->mutex){+.+.}-{3:3}, at: pipe_release+0x48/0x320 fs/pipe.c:727 1 lock held by syz.1.824/9076: #0: ffff88802ca65468 (&pipe->mutex){+.+.}-{3:3}, at: splice_file_to_pipe+0x2e/0x500 fs/splice.c:1292 1 lock held by syz.4.841/9118: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 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:223 [inline] watchdog+0xff4/0x1040 kernel/hung_task.c:379 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9129 Comm: udevd Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:check_preemption_disabled+0x37/0x120 Code: 8b 04 25 28 00 00 00 48 89 44 24 08 65 8b 1d dc d2 3c 74 65 8b 05 d1 d2 3c 74 a9 ff ff ff 7f 74 26 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 0f 85 ce 00 00 00 89 d8 48 83 c4 10 5b 41 5c 41 5e RSP: 0018:ffffc9000a877968 EFLAGS: 00000002 RAX: 73da5ffbe4870a00 RBX: 0000000000000000 RCX: 73da5ffbe4870a00 RDX: dffffc0000000000 RSI: ffffffff8c0adc40 RDI: ffffffff8c60fb20 RBP: ffffc9000a877ae8 R08: ffffffff942cc8af R09: 1ffffffff2859915 R10: dffffc0000000000 R11: fffffbfff2859916 R12: 1ffff9200150ef3c R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000046 FS: 00007fd53fea9c80(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555677764a8 CR3: 000000007c00a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] lock_acquire+0x1fd/0x550 kernel/locking/lockdep.c:5827 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0xd3/0x120 kernel/locking/spinlock.c:326 ep_start_scan fs/eventpoll.c:715 [inline] ep_send_events fs/eventpoll.c:1836 [inline] ep_poll fs/eventpoll.c:2005 [inline] do_epoll_wait+0x838/0x2040 fs/eventpoll.c:2459 __do_sys_epoll_wait fs/eventpoll.c:2471 [inline] __se_sys_epoll_wait fs/eventpoll.c:2466 [inline] __x64_sys_epoll_wait+0x257/0x2a0 fs/eventpoll.c:2466 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd53fb23457 Code: 73 01 c3 48 8b 0d d1 d9 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 e8 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 76 48 8b 15 a2 d9 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffde3537b58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd53fb23457 RDX: 0000000000000004 RSI: 00007ffde3537b98 RDI: 0000000000000004 RBP: 00007ffde3537ba4 R08: 0000000000000007 R09: 49d4b9fc40e75e4e R10: 00000000ffffffff R11: 0000000000000246 R12: 00005654af26ea80 R13: 00007ffde3537b98 R14: 0000000000000001 R15: 00005654af264910