INFO: task syz-executor4:8497 blocked for more than 140 seconds. Not tainted 4.19.0-rc2+ #220 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D24016 8497 4658 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x87c/0x1df0 kernel/sched/core.c:3473 schedule+0xfb/0x450 kernel/sched/core.c:3517 __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:773 [inline] lock_rename+0x236/0x290 fs/namei.c:2862 do_renameat2+0x69e/0x1120 fs/namei.c:4577 __do_sys_rename fs/namei.c:4673 [inline] __se_sys_rename fs/namei.c:4671 [inline] __x64_sys_rename+0x5e/0x80 fs/namei.c:4671 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457099 Code: 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 54 24 38 4c 8b 54 24 18 e9 ee fe ff ff 48 89 74 RSP: 002b:00007fc7e0b3ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007fc7e0b3b6d4 RCX: 0000000000457099 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000020000300 RBP: 00000000009301e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d4008 R14: 00000000004c88c1 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/791: #0: 00000000c44e8e63 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by rsyslogd/4516: #0: 00000000e4997086 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4607: #0: 00000000d3b41051 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000811dc7b9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4608: #0: 00000000beec00b1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000dea6701a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4609: #0: 0000000094accb4f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007c94dd78 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4610: #0: 00000000503a90b8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000de6d5276 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4611: #0: 000000003822bef0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a1952aed (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4612: #0: 00000000e8e8cc69 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000fd41a897 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4613: #0: 000000001b21358a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b4506afd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor4/8441: #0: 00000000ac5403bf (sb_writers#17){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000ac5403bf (sb_writers#17){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000cc2b319e (&sb->s_type->i_mutex_key#23/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000cc2b319e (&sb->s_type->i_mutex_key#23/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2862 2 locks held by syz-executor4/8497: #0: 00000000ac5403bf (sb_writers#17){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000ac5403bf (sb_writers#17){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000cc2b319e (&sb->s_type->i_mutex_key#23/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000cc2b319e (&sb->s_type->i_mutex_key#23/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2862 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 791 Comm: khungtaskd Not tainted 4.19.0-rc2+ #220 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:204 [inline] watchdog+0xb39/0x1040 kernel/hung_task.c:265 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:57