INFO: task syz-executor.2:32704 blocked for more than 140 seconds. Not tainted 4.9.141+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28824 32704 2124 0x00000004 ffff8801cf0c2f80 ffff8801d48e1080 ffff88015d571b80 ffff8801cf4fdf00 ffff8801db721018 ffff8801472bfcf8 ffffffff828075c2 0000000000000000 ffff8801cf0c3830 ffffed0039e18705 00ff8801cf0c2f80 ffff8801db7218f0 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3553 [] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586 [] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [] mutex_lock_nested+0x38d/0x900 kernel/locking/mutex.c:621 [] evdev_flush+0x72/0x120 drivers/input/evdev.c:350 [] filp_close+0xa7/0x140 fs/open.c:1129 [] __close_fd+0x156/0x230 fs/file.c:651 [] SYSC_close fs/open.c:1148 [inline] [] SyS_close+0x4c/0x90 fs/open.c:1146 [] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/24: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by getty/2036: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor.4/14026: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor.2/32704: #0: (&evdev->mutex){+.+.+.}, at: [] evdev_flush+0x72/0x120 drivers/input/evdev.c:350 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #1 ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810983b0 ffff8801d9907d40 ffffffff81b4df89 0000000000000000 0000000000000000 0000000000000002 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6ad/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 32453 Comm: syz-executor.1 Not tainted 4.9.141+ #1 task: ffff8801cb434740 task.stack: ffff8801cf618000 RIP: 0010:[] c [] trace_hardirqs_on_caller+0x35a/0x590 kernel/locking/lockdep.c:2737 RSP: 0018:ffff8801cf61fee0 EFLAGS: 00000803 RAX: dffffc0000000000 RBX: ffff8801cb434740 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801cb434fec RBP: ffff8801cf61fef0 R08: ffff8801cb434ff0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 000000000ba94e8d R13: 000000000000000c R14: 000000000000000d R15: 00000000ffffffff FS: 00007fbbdb65f700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020ab9000 CR3: 00000001d419b000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: 0000000000000009c 000000000000000bc ffff8801cf61ff48c ffffffff8100226ac 0000000000000001c 0000000000000000c 0000000000000001c ffff8801cb434ff0c 0000000000000000c 0000000000000000c 1ffff100396868e9c ffffffff8100584bc Call Trace: [] trace_hardirqs_on_thunk+0x1a/0x1c [] entry_SYSCALL_64_after_swapgs+0x8a/0xdb Code: c89 ca3 c70 c08 c00 c00 c65 c48 c8b c1c c25 c00 c7e c01 c00 c48 c8d cbb cac c08 c00 c00 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c48 c89 cfa c48 cc1 cea c03 c0f cb6 c14 c02 c<48> c89 cf8 c83 ce0 c07 c83 cc0 c03 c38 cd0 c7c c08 c84 cd2 c0f c85 ccd c00 c00 c00 c