kworker/u4:5(7488): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:5(7488): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:5(7488): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:5(7488): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:5(7488): getblk(): executed=9 bh_count=0 bh_state=0 INFO: task syz-executor1:12083 blocked for more than 140 seconds. Not tainted 4.19.0-rc2-next-20180904+ #55 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D25464 12083 4694 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:2424 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: 0033:0x457099 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:00007ff23fdc7c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007ff23fdc86d4 RCX: 0000000000457099 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6b40 R14: 00000000004c84ee R15: 0000000000000001 INFO: task syz-executor1:12128 blocked for more than 140 seconds. Not tainted 4.19.0-rc2-next-20180904+ #55 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D24616 12128 4694 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:2424 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: 0033:0x457099 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:00007ff23fda6c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007ff23fda76d4 RCX: 0000000000457099 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000009301e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6b40 R14: 00000000004c84ee R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/792: #0: 00000000b8e58437 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by rsyslogd/4551: 2 locks held by getty/4642: #0: 000000009dd7515d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000023c4dadb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4643: #0: 00000000c9b1080e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c61f3fd0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4644: #0: 0000000013428f7c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a51ffd42 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4645: #0: 000000004867b499 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000054972cc4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4646: #0: 0000000084264b5a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000027b08c66 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4647: #0: 000000000f6c1680 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000022035ae6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4648: #0: 0000000075ee3f11 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000f540d4e4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 3 locks held by kworker/u4:5/7488: 1 lock held by syz-executor1/12083: #0: 00000000d399fb4e (&fc->fs_type->s_umount_key#58){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:720 1 lock held by syz-executor1/12128: #0: 00000000d399fb4e (&fc->fs_type->s_umount_key#58){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:720 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 792 Comm: khungtaskd Not tainted 4.19.0-rc2-next-20180904+ #55 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 1 to CPUs 0: INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.563 msecs NMI backtrace for cpu 0 CPU: 0 PID: 7488 Comm: kworker/u4:5 Not tainted 4.19.0-rc2-next-20180904+ #55 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:6) RIP: 0010:init_page_buffers+0x427/0x530 fs/buffer.c:894 Code: 39 9d 70 ff ff ff 0f 85 86 fe ff ff e8 52 37 a5 ff 48 8b 8d 50 ff ff ff 48 b8 00 00 00 00 00 fc ff df 48 c7 04 01 00 00 00 00 <48> 8b 85 60 ff ff ff 48 8b 4d d0 65 48 33 0c 25 28 00 00 00 0f 85 RSP: 0018:ffff88018ce96308 EFLAGS: 00000293 RAX: dffffc0000000000 RBX: ffff8801bc55fb28 RCX: 1ffff100319d2c66 RDX: 0000000000000000 RSI: ffffffff81d79f1e RDI: ffff8801b248aa88 RBP: ffff88018ce963b8 R08: ffff8801d28c62c0 R09: ffffed003b6046de R10: 0000000000000003 R11: 0000000000000003 R12: dffffc0000000000 R13: 0000000000000048 R14: 0000000000000001 R15: 0000000000000020 FS: 0000000000000000(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000002637000 CR3: 00000001be9be000 CR4: 00000000001406f0 Call Trace: grow_dev_page fs/buffer.c:954 [inline] grow_buffers fs/buffer.c:1029 [inline] __getblk_slow fs/buffer.c:1062 [inline] __getblk_gfp+0xb56/0xe00 fs/buffer.c:1351 __bread_gfp+0x2d/0x310 fs/buffer.c:1385 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:1183 [inline] __writeback_single_inode+0xd8e/0x1330 fs/fs-writeback.c:1382 writeback_sb_inodes+0x71f/0x1150 fs/fs-writeback.c:1587 __writeback_inodes_wb+0x1b8/0x340 fs/fs-writeback.c:1656 wb_writeback+0x989/0xe80 fs/fs-writeback.c:1765 wb_check_old_data_flush fs/fs-writeback.c:1867 [inline] wb_do_writeback fs/fs-writeback.c:1920 [inline] wb_workfn+0xee6/0x1610 fs/fs-writeback.c:1949 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