INFO: task syz-executor4:9799 blocked for more than 140 seconds. Not tainted 4.18.0+ #194 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D25592 9799 4487 0x00000004 Call Trace: context_switch kernel/sched/core.c:2823 [inline] __schedule+0x87c/0x1ec0 kernel/sched/core.c:3471 schedule+0xfb/0x450 kernel/sched/core.c:3515 __rwsem_down_write_failed_common+0x98b/0x1650 kernel/locking/rwsem-xadd.c:566 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write_nested+0xae/0x130 kernel/locking/rwsem.c:194 inode_lock_nested include/linux/fs.h:765 [inline] lock_rename+0x236/0x290 fs/namei.c:2821 do_renameat2+0x69e/0x1120 fs/namei.c:4530 __do_sys_rename fs/namei.c:4626 [inline] __se_sys_rename fs/namei.c:4624 [inline] __x64_sys_rename+0x5e/0x80 fs/namei.c:4624 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457089 Code: 08 e8 3b a9 fb ff 48 8b 44 24 20 48 8b 4c 24 18 48 8b 54 24 38 48 8b 7c 24 48 eb 8d 48 8b 6c 24 50 48 83 c4 58 c3 48 89 04 24 <48> 89 5c 24 08 e8 0d a9 fb ff 48 8b 44 24 40 48 8b 4c 24 48 48 8b RSP: 002b:00007f4598842c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007f45988436d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 00000000200000c0 RBP: 0000000000930280 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3890 R14: 00000000004c851a R15: 0000000000000003 Showing all locks held in the system: 1 lock held by khungtaskd/776: #0: 0000000020afe2ee (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4350: 2 locks held by getty/4440: #0: 00000000ef630bdf (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000d846ca11 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4441: #0: 0000000017da63f2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003edfc23d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4442: #0: 0000000075832bdb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a901457d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4443: #0: 000000000e0e9ca5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008e852365 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4444: #0: 00000000346c68c9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000005d9d93e2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4445: #0: 00000000e34f6f0f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000056f08ef9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4446: #0: 00000000c9a88652 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000073ec13fc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor4/9721: #0: 00000000f1f4f308 (sb_writers#18){.+.+}, at: sb_start_write include/linux/fs.h:1569 [inline] #0: 00000000f1f4f308 (sb_writers#18){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 00000000d626cdcf (&sb->s_type->i_mutex_key#21/1){+.+.}, at: inode_lock_nested include/linux/fs.h:765 [inline] #1: 00000000d626cdcf (&sb->s_type->i_mutex_key#21/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2821 2 locks held by syz-executor4/9799: #0: 00000000f1f4f308 (sb_writers#18){.+.+}, at: sb_start_write include/linux/fs.h:1569 [inline] #0: 00000000f1f4f308 (sb_writers#18){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 00000000d626cdcf (&sb->s_type->i_mutex_key#21/1){+.+.}, at: inode_lock_nested include/linux/fs.h:765 [inline] #1: 00000000d626cdcf (&sb->s_type->i_mutex_key#21/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2821 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 776 Comm: khungtaskd Not tainted 4.18.0+ #194 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x48/0x88 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x9c4/0xf80 kernel/hung_task.c:252 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:56