xt_nfacct: accounting object `syz0' does not exists INFO: task syz-executor5:11536 blocked for more than 140 seconds. Not tainted 4.18.0-next-20180820+ #43 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D25104 11536 4515 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+0xaa/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:765 [inline] vfs_removexattr+0x82/0x1c0 fs/xattr.c:390 removexattr+0xd3/0x130 fs/xattr.c:690 path_removexattr+0x1b9/0x210 fs/xattr.c:704 __do_sys_removexattr fs/xattr.c:718 [inline] __se_sys_removexattr fs/xattr.c:715 [inline] __x64_sys_removexattr+0x59/0x80 fs/xattr.c:715 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:00007fcf4a0a0c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000c5 RAX: ffffffffffffffda RBX: 00007fcf4a0a16d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000020000080 RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3878 R14: 00000000004c3451 R15: 0000000000000001 Showing all locks held in the system: 1 lock held by khungtaskd/775: #0: 0000000007648613 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by rsyslogd/4373: #0: 0000000041264a74 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4463: #0: 00000000de14ae8a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007ec53763 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4464: #0: 00000000e7482e12 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001b1548fc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4465: #0: 0000000064ee845e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006d8c52db (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4466: #0: 00000000af99406b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006eb9241e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4467: #0: 00000000d1e09ad0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b3a59fb2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4468: #0: 00000000adfa0bef (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ebd1902d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4469: #0: 00000000fb2cc60d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000294b88ea (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor5/11522: #0: 00000000e0ea0c24 (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1598 [inline] #0: 00000000e0ea0c24 (sb_writers#14){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000c5f914d7 (&sb->s_type->i_mutex_key#20){+.+.}, at: inode_lock include/linux/fs.h:765 [inline] #1: 00000000c5f914d7 (&sb->s_type->i_mutex_key#20){+.+.}, at: vfs_removexattr+0x82/0x1c0 fs/xattr.c:390 2 locks held by syz-executor5/11536: #0: 00000000e0ea0c24 (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1598 [inline] #0: 00000000e0ea0c24 (sb_writers#14){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000c5f914d7 (&sb->s_type->i_mutex_key#20){+.+.}, at: inode_lock include/linux/fs.h:765 [inline] #1: 00000000c5f914d7 (&sb->s_type->i_mutex_key#20){+.+.}, at: vfs_removexattr+0x82/0x1c0 fs/xattr.c:390 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 775 Comm: khungtaskd Not tainted 4.18.0-next-20180820+ #43 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:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.18.0-next-20180820+ #43 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__preempt_count_sub arch/x86/include/asm/preempt.h:81 [inline] RIP: 0010:trace_softirq_raise include/trace/events/irq.h:156 [inline] RIP: 0010:__raise_softirq_irqoff kernel/softirq.c:450 [inline] RIP: 0010:raise_softirq_irqoff+0x20b/0x2e0 kernel/softirq.c:424 Code: 89 e0 48 8d 55 d8 48 c1 e8 03 42 80 3c 38 00 0f 85 97 00 00 00 4d 8b 34 24 4d 85 f6 75 b9 65 ff 0d 0a 6d b8 7e e9 78 fe ff ff <65> ff 05 fe 6c b8 7e 48 b9 00 00 00 00 00 fc ff df 48 8d 42 c0 48 RSP: 0018:ffff8801db107c18 EFLAGS: 00000047 RAX: 0000000000000001 RBX: 1ffff1003b620f83 RCX: ffffffff87cd3ec8 RDX: ffff8801db107cb8 RSI: 1ffff1003b620fc5 RDI: 0000000000000007 RBP: ffff8801db107ce0 R08: 1ffff1003b625acd R09: ffffed003b625999 R10: ffffed003b625999 R11: ffff8801db12cccb R12: ffff8801d9f1a380 R13: 0000000000000007 R14: ffff8801db107e68 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001e7d000 CR3: 00000001afe6c000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: scheduler_ipi+0x6c7/0xa50 kernel/sched/core.c:1778 smp_reschedule_interrupt+0xfd/0x5e0 arch/x86/kernel/smp.c:278 reschedule_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:891 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:56 Code: c7 48 89 45 d8 e8 ca 09 05 fb 48 8b 45 d8 e9 d2 fe ff ff 48 89 df e8 b9 09 05 fb eb 8a 90 90 90 90 90 90 90 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 90 90 90 90 90 RSP: 0018:ffff8801d9f27c30 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1003b3e4f8a RCX: 0000000000000000 RDX: 1ffffffff0fe3780 RSI: 0000000000000001 RDI: ffffffff87f1bc00 RBP: ffff8801d9f27c30 R08: ffff8801d9f1a380 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801d9f27cf0 R14: 0000000000000001 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0xc2/0x410 arch/x86/kernel/process.c:498 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:489 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x3aa/0x580 kernel/sched/idle.c:262 cpu_startup_entry+0x10c/0x120 kernel/sched/idle.c:368 start_secondary+0x433/0x5d0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242