kworker/u4:0(7): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:0(7): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:0(7): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:0(7): getblk(): executed=9 bh_count=0 bh_state=0 kworker/u4:0(7): getblk(): executed=9 bh_count=0 bh_state=0 INFO: task syz-executor4:2701 blocked for more than 140 seconds. Not tainted 4.20.0-rc7-next-20181224 #188 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D24264 2701 8167 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x9de/0x1ed0 kernel/sched/core.c:3472 schedule+0xef/0x370 kernel/sched/core.c:3516 wb_wait_for_completion+0x1f9/0x2d0 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:724 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: 0033:0x457759 Code: Bad RIP value. RSP: 002b:00007fca1258fc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 000000000073bf08 RCX: 0000000000457759 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fca125906d4 R13: 00000000004c3922 R14: 00000000004da500 R15: 00000000ffffffff INFO: task syz-executor4:2751 blocked for more than 140 seconds. Not tainted 4.20.0-rc7-next-20181224 #188 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D24528 2751 8167 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x9de/0x1ed0 kernel/sched/core.c:3472 schedule+0xef/0x370 kernel/sched/core.c:3516 wb_wait_for_completion+0x1f9/0x2d0 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:724 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: 0033:0x457759 Code: Bad RIP value. RSP: 002b:00007fca1254dc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 000000000073c048 RCX: 0000000000457759 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fca1254e6d4 R13: 00000000004c3922 R14: 00000000004da500 R15: 00000000ffffffff Showing all locks held in the system: 5 locks held by kworker/u4:0/7: 1 lock held by khungtaskd/1033: #0: 00000000492d82a5 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4389 1 lock held by rsyslogd/7975: #0: 00000000638eb3f4 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:795 2 locks held by getty/8065: #0: 00000000d72ec77a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000007a66e03f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8066: #0: 000000006fa3a7b3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d3a4dfc1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8067: #0: 00000000073e76ed (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000004272216f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8068: #0: 00000000339b173d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000dba23be7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8069: #0: 000000001a50a80f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000cbfbf426 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8070: #0: 00000000fc4cf7d1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000000fe1461d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8071: #0: 00000000daf4971a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000008b7958d7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by syz-executor0/6239: #0: 00000000bac6578c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000e82549a5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 1 lock held by syz-executor4/2701: #0: 000000008743ac47 (&fc->fs_type->s_umount_key#75){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:722 1 lock held by syz-executor4/2751: #0: 000000008743ac47 (&fc->fs_type->s_umount_key#75){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:722 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1033 Comm: khungtaskd Not tainted 4.20.0-rc7-next-20181224 #188 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+0x1d3/0x2c6 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1c2/0x22c 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+0xba1/0x11a0 kernel/hung_task.c:287 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.291 msecs NMI backtrace for cpu 0 CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 4.20.0-rc7-next-20181224 #188 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:__lock_acquire+0x409/0x4c20 kernel/locking/lockdep.c:3283 Code: 10 00 00 41 8b b3 6c 08 00 00 49 8d 7f 24 31 d2 85 f6 44 89 f6 0f 95 c2 41 83 e1 01 c1 e6 07 01 c2 41 0f b6 47 21 41 c1 e1 03 <83> e2 03 c1 e2 05 83 e0 1f 09 d0 89 ca 41 0f b6 4f 22 41 89 c6 44 RSP: 0018:ffff8881d9ac5e20 EFLAGS: 00000046 RAX: 0000000000000002 RBX: 0000000000000229 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881d9abab04 RBP: ffff8881d9ac61a8 R08: 0000000000000001 R09: 0000000000000000 R10: 00000000000000a0 R11: ffff8881d9aba1c0 R12: 0000000000000004 R13: ffff8881d9abaa2c R14: 0000000000000000 R15: ffff8881d9abaae0 FS: 0000000000000000(0000) GS:ffff8881dac00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001cdb91000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3841 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] __find_get_block_slow fs/buffer.c:209 [inline] __find_get_block+0x661/0xf20 fs/buffer.c:1325 __getblk_slow fs/buffer.c:1058 [inline] __getblk_gfp+0x3d3/0x1030 fs/buffer.c:1351 __bread_gfp+0x2d/0x300 fs/buffer.c:1385 sb_bread include/linux/buffer_head.h:307 [inline] fat_clusters_flush+0x127/0x3c0 fs/fat/misc.c:70 fat_write_inode+0x110/0x180 fs/fat/inode.c:905 write_inode fs/fs-writeback.c:1176 [inline] __writeback_single_inode+0xf56/0x1660 fs/fs-writeback.c:1375 writeback_sb_inodes+0x71f/0x1210 fs/fs-writeback.c:1580 __writeback_inodes_wb+0x1b9/0x340 fs/fs-writeback.c:1649 wb_writeback+0xa73/0xfc0 fs/fs-writeback.c:1758 wb_check_old_data_flush fs/fs-writeback.c:1860 [inline] wb_do_writeback fs/fs-writeback.c:1913 [inline] wb_workfn+0x1008/0x1790 fs/fs-writeback.c:1942 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352