INFO: task syz-executor0:8053 blocked for more than 140 seconds. Not tainted 4.20.0-next-20190107 #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D18520 8053 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3472 schedule+0xfe/0x350 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xa3b/0x1670 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 vfat_lookup+0xed/0x6b0 fs/fat/namei_vfat.c:709 __lookup_slow+0x2cd/0x560 fs/namei.c:1671 lookup_slow+0x58/0x80 fs/namei.c:1688 walk_component+0x8e5/0x26a0 fs/namei.c:1810 link_path_walk.part.0+0xa57/0x1550 fs/namei.c:2141 link_path_walk fs/namei.c:2072 [inline] path_openat+0x222/0x5660 fs/namei.c:3533 do_filp_open+0x26f/0x370 fs/namei.c:3564 do_sys_open+0x59a/0x7c0 fs/open.c:1063 __do_sys_open fs/open.c:1081 [inline] __se_sys_open fs/open.c:1076 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1076 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455ef0 Code: Bad RIP value. RSP: 002b:00007ffdf3922880 EFLAGS: 00000202 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000455ef0 RDX: 0000000000000000 RSI: 0000000000090800 RDI: 00000000004bc9af RBP: 0000000000000575 R08: 0000000000000001 R09: 000000000141a940 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000005 R13: 0000000000065406 R14: 00000000000001fa R15: 0000000000000000 INFO: task syz-executor0:18726 blocked for more than 140 seconds. Not tainted 4.20.0-next-20190107 #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D22168 18726 8053 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3472 schedule+0xfe/0x350 kernel/sched/core.c:3516 d_wait_lookup fs/dcache.c:2408 [inline] d_alloc_parallel+0x143c/0x1f10 fs/dcache.c:2490 __lookup_slow+0x1fa/0x560 fs/namei.c:1654 lookup_slow+0x58/0x80 fs/namei.c:1688 walk_component+0x8e5/0x26a0 fs/namei.c:1810 link_path_walk.part.0+0xa57/0x1550 fs/namei.c:2141 link_path_walk fs/namei.c:2072 [inline] path_openat+0x222/0x5660 fs/namei.c:3533 do_filp_open+0x26f/0x370 fs/namei.c:3564 do_sys_open+0x59a/0x7c0 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 28 c3 e8 aa 20 00 00 eb a8 cc cc cc cc cc cc cc cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 76 2e 48 83 ec 18 48 89 6c 24 10 48 <8d> 6c 24 10 48 8b 42 08 48 8b 4a 10 48 89 04 24 48 89 4c 24 08 e8 RSP: 002b:00007fb2897bcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457ec9 RDX: 0000000000000002 RSI: 0000000020000340 RDI: ffffffffffffff9c RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb2897bd6d4 R13: 00000000004c3f5f R14: 00000000004d7060 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1040: #0: 000000006ce02ebe (rcu_read_lock){....}, at: debug_show_all_locks+0xc6/0x41d kernel/locking/lockdep.c:4389 1 lock held by rsyslogd/7929: #0: 000000009debb2af (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1b3/0x1f0 fs/file.c:795 2 locks held by getty/8019: #0: 00000000dc528c55 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000002475210d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8020: #0: 00000000e897f49d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d1e40770 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8021: #0: 00000000971d78c8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000994e3dbb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8022: #0: 00000000725fb993 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a6e4ed16 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8023: #0: 00000000e0c37046 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000bccf002c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8024: #0: 000000007623d5ff (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f0cf0aa7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8025: #0: 00000000ae584079 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000cb1d0611 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by syz-executor0/8053: #0: 000000009454f6b6 (&sb->s_type->i_mutex_key#20){++++}, at: inode_lock_shared include/linux/fs.h:776 [inline] #0: 000000009454f6b6 (&sb->s_type->i_mutex_key#20){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1687 #1: 00000000176c2124 (&sbi->s_lock){+.+.}, at: vfat_lookup+0xed/0x6b0 fs/fat/namei_vfat.c:709 6 locks held by syz-executor0/18718: 1 lock held by syz-executor0/18726: #0: 000000009454f6b6 (&sb->s_type->i_mutex_key#20){++++}, at: inode_lock_shared include/linux/fs.h:776 [inline] #0: 000000009454f6b6 (&sb->s_type->i_mutex_key#20){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1687 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1040 Comm: khungtaskd Not tainted 4.20.0-next-20190107 #6 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+0x1db/0x2d0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0xbbb/0x1170 kernel/hung_task.c:287 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 18718 Comm: syz-executor0 Not tainted 4.20.0-next-20190107 #6 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:450 Code: e9 00 00 00 49 8d 7c 24 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 17 41 03 5c 24 38 89 da ec <5b> 0f b6 c0 41 5c 5d c3 e8 f8 71 e3 fd eb c2 e8 51 72 e3 fd eb e2 RSP: 0018:ffff88805cae66e8 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff83e2a891 RDI: ffffffff8bf76378 RBP: ffff88805cae66f8 R08: ffff88805ad94500 R09: ffffed100b95cce4 R10: ffffed100b95cce3 R11: 0000000000000003 R12: ffffffff8bf76340 R13: 0000000000000020 R14: 0000000000000000 R15: fffffbfff17eec71 FS: 00007fb2897de700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000021b8000 CR3: 0000000095d0d000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:111 [inline] wait_for_xmitr+0xa7/0x250 drivers/tty/serial/8250/8250_port.c:2028 serial8250_console_putchar+0x20/0x60 drivers/tty/serial/8250/8250_port.c:3199 uart_console_write+0x57/0x120 drivers/tty/serial/serial_core.c:1907 serial8250_console_write+0x6d5/0xab0 drivers/tty/serial/8250/8250_port.c:3263 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:586 call_console_drivers kernel/printk/printk.c:1784 [inline] console_unlock+0xc9a/0x1040 kernel/printk/printk.c:2455 vprintk_emit+0x370/0x960 kernel/printk/printk.c:1978 vprintk_default+0x28/0x30 kernel/printk/printk.c:2005 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2038 __find_get_block_slow fs/buffer.c:237 [inline] __find_get_block fs/buffer.c:1325 [inline] __find_get_block.cold+0xd4/0xfb fs/buffer.c:1319 __getblk_slow fs/buffer.c:1058 [inline] __getblk_gfp+0x3c5/0x1130 fs/buffer.c:1351 __bread_gfp+0x2f/0x300 fs/buffer.c:1385 sb_bread include/linux/buffer_head.h:307 [inline] fat__get_entry+0x586/0xa40 fs/fat/dir.c:101 fat_get_entry fs/fat/dir.c:129 [inline] fat_search_long+0x345/0x17d0 fs/fat/dir.c:479 vfat_find+0x10e/0x140 fs/fat/namei_vfat.c:697 vfat_lookup+0x10a/0x6b0 fs/fat/namei_vfat.c:711 __lookup_slow+0x2cd/0x560 fs/namei.c:1671 lookup_slow+0x58/0x80 fs/namei.c:1688 walk_component+0x8e5/0x26a0 fs/namei.c:1810 link_path_walk.part.0+0xa57/0x1550 fs/namei.c:2141 link_path_walk fs/namei.c:2072 [inline] path_openat+0x222/0x5660 fs/namei.c:3533 do_filp_open+0x26f/0x370 fs/namei.c:3564 do_sys_open+0x59a/0x7c0 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb2897ddc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457ec9 RDX: 0000000000000002 RSI: 0000000020000340 RDI: ffffffffffffff9c RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb2897de6d4 R13: 00000000004c3f5f R14: 00000000004d7060 R15: 00000000ffffffff