INFO: task syz-executor0:17072 blocked for more than 140 seconds. Not tainted 5.0.0-rc1-next-20190111 #10 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D23864 17072 7459 0x80000006 Call Trace: context_switch kernel/sched/core.c:2834 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3475 schedule+0xfe/0x350 kernel/sched/core.c:3519 wb_wait_for_completion+0x1e0/0x2d0 fs/fs-writeback.c:221 __writeback_inodes_sb_nr+0x417/0x590 fs/fs-writeback.c:2333 writeback_inodes_sb_nr fs/fs-writeback.c:2350 [inline] writeback_inodes_sb+0x28/0x30 fs/fs-writeback.c:2365 __sync_filesystem fs/sync.c:36 [inline] sync_filesystem+0x16e/0x340 fs/sync.c:64 generic_shutdown_super+0xd6/0x530 fs/super.c:444 kill_block_super+0xa0/0x100 fs/super.c:1373 deactivate_locked_super+0x9a/0x100 fs/super.c:331 deactivate_super fs/super.c:362 [inline] deactivate_super+0x2ab/0x320 fs/super.c:358 cleanup_mnt+0xbf/0x160 fs/namespace.c:1140 __cleanup_mnt+0x16/0x20 fs/namespace.c:1147 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xad9/0x2af0 kernel/exit.c:874 do_group_exit+0x177/0x430 kernel/exit.c:977 get_signal+0x8b4/0x19b0 kernel/signal.c:2519 do_signal+0x91/0x1ea0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2f7/0x3b0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: Bad RIP value. RSP: 002b:00007fbf390aecf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000073bfa8 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000073bfa8 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000073bfac R13: 00007ffc3f6e033f R14: 00007fbf390af9c0 R15: 000000000073bfac Showing all locks held in the system: 3 locks held by kworker/u4:2/37: #0: 000000007702e496 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1149 [inline] #0: 000000007702e496 (&rq->lock){-.-.}, at: __schedule+0x21e/0x1e60 kernel/sched/core.c:3413 #1: 0000000044db4b84 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:428 [inline] #1: 0000000044db4b84 (rcu_read_lock){....}, at: update_curr+0x362/0xbc0 kernel/sched/fair.c:829 #2: 0000000034503289 (&base->lock){-.-.}, at: lock_timer_base+0xb7/0x2a0 kernel/time/timer.c:937 1 lock held by khungtaskd/1040: #0: 0000000044db4b84 (rcu_read_lock){....}, at: debug_show_all_locks+0xc6/0x41d kernel/locking/lockdep.c:4408 1 lock held by rsyslogd/7310: #0: 0000000076936875 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1b3/0x1f0 fs/file.c:796 2 locks held by getty/7423: #0: 00000000652bb350 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000053a55a11 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/7424: #0: 000000004ec21361 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000001340c6e2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/7425: #0: 00000000d9729558 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000905b1a3d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/7426: #0: 00000000ac64c6c4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d7ae5042 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/7427: #0: 000000000973155b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d7137352 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/7428: #0: 000000006aa7860c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000836ca81a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/7429: #0: 00000000fb881197 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a2f7cd1e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 4 locks held by kworker/u4:5/9268: 1 lock held by syz-executor0/17072: #0: 00000000f839b1c9 (&type->s_umount_key#61){++++}, at: deactivate_super fs/super.c:361 [inline] #0: 00000000f839b1c9 (&type->s_umount_key#61){++++}, at: deactivate_super+0x2a3/0x320 fs/super.c:358 1 lock held by syz-executor4/19693: #0: 00000000f839b1c9 (&type->s_umount_key#61){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:721 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1040 Comm: khungtaskd Not tainted 5.0.0-rc1-next-20190111 #10 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:247 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9268 Comm: kworker/u4:5 Not tainted 5.0.0-rc1-next-20190111 #10 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x50 kernel/kcov.c:100 Code: 70 d5 09 00 00 00 00 48 89 85 68 fe ff ff e9 85 df ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 48 8b 75 08 <65> 48 8b 04 25 40 ee 01 00 65 8b 15 18 c1 7f 7e 81 e2 00 01 1f 00 RSP: 0018:ffff8880672766c0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff8392d85a RDX: 0000000000000001 RSI: ffffffff8392d863 RDI: 0000000000000005 RBP: ffff8880672766c0 R08: ffff888066bbc5c0 R09: ffffed1015cc5b90 R10: ffffed1015cc5b8f R11: ffff8880ae62dc7b R12: ffffffff88820960 R13: 0000000000000000 R14: ffffffff88820920 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001231000 CR3: 000000009f953000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: check_preemption_disabled+0x43/0x290 lib/smp_processor_id.c:15 debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:56 rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1003 [inline] rcu_lockdep_current_cpu_online+0xc6/0x220 kernel/rcu/tree.c:994 rcu_read_lock_held+0x8a/0xd0 kernel/rcu/update.c:279 xa_head include/linux/xarray.h:988 [inline] xas_start+0x2b6/0x700 lib/xarray.c:182 xas_load+0x21/0x150 lib/xarray.c:227 find_get_entry+0x353/0x1090 mm/filemap.c:1476 pagecache_get_page+0xe5/0x1070 mm/filemap.c:1582 find_or_create_page include/linux/pagemap.h:323 [inline] grow_dev_page fs/buffer.c:947 [inline] grow_buffers fs/buffer.c:1029 [inline] __getblk_slow fs/buffer.c:1062 [inline] __getblk_gfp+0x4e2/0x1140 fs/buffer.c:1357 __bread_gfp+0x2f/0x300 fs/buffer.c:1391 sb_bread include/linux/buffer_head.h:307 [inline] fat_clusters_flush+0x127/0x3c0 fs/fat/misc.c:70 fat_write_inode fs/fat/inode.c:905 [inline] fat_write_inode+0x111/0x190 fs/fat/inode.c:897 write_inode fs/fs-writeback.c:1176 [inline] __writeback_single_inode+0xef1/0x1620 fs/fs-writeback.c:1375 writeback_sb_inodes+0x762/0x1260 fs/fs-writeback.c:1580 wb_writeback+0x338/0xf70 fs/fs-writeback.c:1756 wb_do_writeback fs/fs-writeback.c:1901 [inline] wb_workfn+0x416/0x16f0 fs/fs-writeback.c:1942 process_one_work+0xd0c/0x1ce0 kernel/workqueue.c:2153 worker_thread+0x143/0x14a0 kernel/workqueue.c:2296 kthread+0x357/0x430 kernel/kthread.c:247 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352