kworker/u4:4(255): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:4(255): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:4(255): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:4(255): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:4(255): getblk(): executed=9 bh_count=0 bh_state=0 INFO: task syz-executor3:25113 blocked for more than 140 seconds. Not tainted 4.18.0-next-20180823+ #46 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D25408 25113 4485 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 wb_wait_for_completion+0x201/0x2e0 fs/fs-writeback.c:221 sync_inodes_sb+0x33e/0x480 fs/fs-writeback.c:2417 sync_inodes_one_sb+0x59/0x70 fs/sync.c:74 iterate_supers+0x149/0x290 fs/super.c:722 ksys_sync+0xec/0x1e0 fs/sync.c:113 __ia32_sys_sync+0xe/0x20 fs/sync.c:124 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:00007fcfb23aec78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fcfb23af6d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6350 R14: 00000000004c8147 R15: 0000000000000000 INFO: task syz-executor3:25121 blocked for more than 140 seconds. Not tainted 4.18.0-next-20180823+ #46 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D25408 25121 4485 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 wb_wait_for_completion+0x201/0x2e0 fs/fs-writeback.c:221 sync_inodes_sb+0x33e/0x480 fs/fs-writeback.c:2417 sync_inodes_one_sb+0x59/0x70 fs/sync.c:74 iterate_supers+0x149/0x290 fs/super.c:722 ksys_sync+0xec/0x1e0 fs/sync.c:113 __ia32_sys_sync+0xe/0x20 fs/sync.c:124 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:00007fcfb238dc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fcfb238e6d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6350 R14: 00000000004c8147 R15: 0000000000000001 Showing all locks held in the system: 4 locks held by kworker/u4:4/255: 1 lock held by khungtaskd/776: #0: 000000005d6907ec (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by rsyslogd/4348: #0: 0000000047a29f76 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4438: #0: 00000000672e0d04 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000001ddd244 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4439: #0: 00000000a979dd62 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007a7db0a7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4440: #0: 0000000036ba1e6b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ff0dac43 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4441: #0: 00000000407ade15 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000bf271ebf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4442: #0: 000000001a24c535 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000000ee1ced7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4443: #0: 00000000796b5a77 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008b942d8c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4444: #0: 000000002e14e23d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008fd5dadc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 1 lock held by syz-executor3/25113: #0: 000000009c844de2 (&fc->fs_type->s_umount_key#66){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:720 1 lock held by syz-executor3/25121: #0: 000000009c844de2 (&fc->fs_type->s_umount_key#66){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:720 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 776 Comm: khungtaskd Not tainted 4.18.0-next-20180823+ #46 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: INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.011 msecs NMI backtrace for cpu 1 CPU: 1 PID: 255 Comm: kworker/u4:4 Not tainted 4.18.0-next-20180823+ #46 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:rcu_is_watching+0x110/0x150 kernel/rcu/tree.c:1028 Code: 13 f8 65 ff 0d f1 e4 9a 7e 49 c7 04 14 00 00 00 00 d1 e8 83 e0 01 48 8b 75 d0 65 48 33 34 25 28 00 00 00 75 32 48 83 c4 68 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 89 df 89 85 74 ff ff ff e8 d8 e9 RSP: 0018:ffff8801d9015b60 EFLAGS: 00000282 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1ffff1003b202b63 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8801db1236f0 RBP: ffff8801d9015b80 R08: ffffed003b6246df R09: ffffed003b6246de R10: ffffed003b6246de R11: ffff8801db1236f3 R12: 1ffff1003b202b5f R13: ffff8801db1236f0 R14: ffff8801d9015b58 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001b3493000 CR4: 00000000001406e0 Call Trace: rcu_read_lock include/linux/rcupdate.h:630 [inline] find_get_entry+0xce3/0x1120 mm/filemap.c:1397 pagecache_get_page+0x11e/0xe40 mm/filemap.c:1503 find_get_page_flags include/linux/pagemap.h:278 [inline] __find_get_block_slow fs/buffer.c:206 [inline] __find_get_block+0x5b1/0xdf0 fs/buffer.c:1326 __getblk_slow fs/buffer.c:1059 [inline] __getblk_gfp+0x3dc/0xe00 fs/buffer.c:1352 __bread_gfp+0x2d/0x310 fs/buffer.c:1386 sb_bread include/linux/buffer_head.h:307 [inline] __fat_write_inode+0x347/0xb60 fs/fat/inode.c:860 fat_write_inode+0x97/0x180 fs/fat/inode.c:909 write_inode fs/fs-writeback.c:1176 [inline] __writeback_single_inode+0xdc5/0x1380 fs/fs-writeback.c:1375 writeback_sb_inodes+0x71f/0x11a0 fs/fs-writeback.c:1580 __writeback_inodes_wb+0x1b8/0x340 fs/fs-writeback.c:1649 wb_writeback+0x989/0xe80 fs/fs-writeback.c:1758 wb_check_start_all fs/fs-writeback.c:1882 [inline] wb_do_writeback fs/fs-writeback.c:1908 [inline] wb_workfn+0xdcf/0x1610 fs/fs-writeback.c:1942 process_one_work+0xc73/0x1aa0 kernel/workqueue.c:2153 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415