Buffer I/O error on dev loop0, logical block 0, async page read INFO: task syz-executor7:4237 blocked for more than 120 seconds. Not tainted 4.16.0-rc3+ #330 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor7 D22160 4237 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x905/0x2070 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3557 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 xt_request_find_table_lock+0x28/0xc0 net/netfilter/x_tables.c:1087 get_info+0x154/0x690 net/ipv6/netfilter/ip6_tables.c:993 do_ip6t_get_ctl+0x159/0xaf0 net/ipv6/netfilter/ip6_tables.c:1714 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline] nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:122 ipv6_getsockopt+0x1d5/0x2c0 net/ipv6/ipv6_sockglue.c:1370 tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3359 sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2934 SYSC_getsockopt net/socket.c:1880 [inline] SyS_getsockopt+0x178/0x340 net/socket.c:1862 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45683a RSP: 002b:0000000000a3e3b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 0000000000a3e3e0 RCX: 000000000045683a RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000013 RBP: 00000000006fd720 R08: 0000000000a3e3dc R09: 0000000000004000 R10: 0000000000a3e3e0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000013 R14: 0000000000000029 R15: 00000000006fb560 Showing all locks held in the system: 2 locks held by khungtaskd/794: #0: (rcu_read_lock){....}, at: [<00000000f2e23315>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000f2e23315>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000e9297713>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4040: #0: (&f->f_pos_lock){+.+.}, at: [<0000000082cca4c6>] __fdget_pos+0x12b/0x190 fs/file.c:765 2 locks held by getty/4162: #0: (&tty->ldisc_sem){++++}, at: [<000000005f2fb7f7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000004c165f9>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4163: #0: (&tty->ldisc_sem){++++}, at: [<000000005f2fb7f7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000004c165f9>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4164: #0: (&tty->ldisc_sem){++++}, at: [<000000005f2fb7f7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000004c165f9>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4165: #0: (&tty->ldisc_sem){++++}, at: [<000000005f2fb7f7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000004c165f9>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4166: #0: (&tty->ldisc_sem){++++}, at: [<000000005f2fb7f7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000004c165f9>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4167: #0: (&tty->ldisc_sem){++++}, at: [<000000005f2fb7f7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000004c165f9>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor7/4237: #0: (&xt[i].mutex){+.+.}, at: [<0000000005236191>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor4/4242: #0: (&xt[i].mutex){+.+.}, at: [<0000000005236191>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor6/4244: #0: (&xt[i].mutex){+.+.}, at: [<0000000005236191>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor5/4245: #0: (&xt[i].mutex){+.+.}, at: [<0000000005236191>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor1/4247: #0: (&xt[i].mutex){+.+.}, at: [<0000000005236191>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor2/23072: #0: (&xt[i].mutex){+.+.}, at: [<0000000005236191>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 2 locks held by getty/32490: #0: (&tty->ldisc_sem){++++}, at: [<000000005f2fb7f7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000004c165f9>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor3/10669: #0: (&xt[i].mutex){+.+.}, at: [<00000000f378abbd>] xt_find_target+0x44/0x1e0 net/netfilter/x_tables.c:231 1 lock held by syz-executor3/10671: #0: (&xt[i].mutex){+.+.}, at: [<00000000f378abbd>] xt_find_target+0x44/0x1e0 net/netfilter/x_tables.c:231 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 794 Comm: khungtaskd Not tainted 4.16.0-rc3+ #330 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 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:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:407 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6909 Comm: syz-executor0 Not tainted 4.16.0-rc3+ #330 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:match_held_lock+0xcb/0x880 kernel/locking/lockdep.c:3495 RSP: 0018:ffff8801af8ef4f8 EFLAGS: 00000046 RAX: 0000000000000003 RBX: 1ffff10035f1dea4 RCX: 0000000000000006 RDX: 0000000000000000 RSI: ffffffff86f42800 RDI: ffff8801d4ff2c9a RBP: ffff8801af8ef5e8 R08: 1ffff10035f1dea7 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d4ff2400 R13: ffff8801d4ff2c78 R14: 0000000000000000 R15: ffff8801af8ef5c0 FS: 000000000138c940(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbde502e000 CR3: 00000001cdb7c003 CR4: 00000000001626e0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: __lock_is_held+0xb6/0x140 kernel/locking/lockdep.c:3740 lock_is_held_type+0x118/0x210 kernel/locking/lockdep.c:3958 lock_is_held include/linux/lockdep.h:344 [inline] rcu_preempt_sleep_check include/linux/rcupdate.h:301 [inline] ___might_sleep+0x35e/0x470 kernel/sched/core.c:6098 htable_selective_cleanup+0x29c/0x3d0 net/netfilter/xt_hashlimit.c:381 htable_destroy net/netfilter/xt_hashlimit.c:415 [inline] htable_put+0x1de/0x300 net/netfilter/xt_hashlimit.c:442 hashlimit_mt_destroy+0x56/0x70 net/netfilter/xt_hashlimit.c:979 cleanup_match+0x14e/0x220 net/ipv6/netfilter/ip6_tables.c:485 cleanup_entry+0xef/0x380 net/ipv6/netfilter/ip6_tables.c:669 __do_replace+0x7ac/0xa70 net/ipv6/netfilter/ip6_tables.c:1112 do_replace net/ipv6/netfilter/ip6_tables.c:1168 [inline] do_ip6t_set_ctl+0x40f/0x5f0 net/ipv6/netfilter/ip6_tables.c:1690 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt+0x10b/0x130 net/ipv6/ipv6_sockglue.c:927 tcp_setsockopt+0x82/0xd0 net/ipv4/tcp.c:2905 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2975 SYSC_setsockopt net/socket.c:1849 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1828 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45685a RSP: 002b:0000000000a3e3b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000a3e3e0 RCX: 000000000045685a RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000013 RBP: 00000000006fd720 R08: 00000000000002e8 R09: 0000000000004000 R10: 00000000006fc940 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000013 R14: 0000000000000029 R15: 00000000006fc9a0 Code: 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 9d 04 00 00 66 41 f7 45 22 f0 ff <0f> 84 f9 01 00 00 48 8d 7e 08 48 b8 00 00 00 00 00 fc ff df 48