Out of memory: Kill process 21254 (syz-executor.5) score 1007 or sacrifice child Killed process 21254 (syz-executor.5) total-vm:75368kB, anon-rss:16548kB, file-rss:34816kB, shmem-rss:0kB oom_reaper: reaped process 21254 (syz-executor.5), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB INFO: task syz-executor.4:6351 blocked for more than 140 seconds. Not tainted 4.14.182-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D25104 6351 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 wb_wait_for_completion fs/fs-writeback.c:221 [inline] wb_wait_for_completion+0x118/0x170 fs/fs-writeback.c:217 __writeback_inodes_sb_nr+0x168/0x1d0 fs/fs-writeback.c:2357 __sync_filesystem fs/sync.c:36 [inline] sync_filesystem+0x8c/0x230 fs/sync.c:64 ovl_sync_fs+0xa8/0xe0 fs/overlayfs/super.c:259 __sync_filesystem fs/sync.c:39 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x185/0x230 fs/sync.c:48 generic_shutdown_super+0x70/0x370 fs/super.c:432 kill_anon_super+0x38/0x50 fs/super.c:1006 deactivate_locked_super+0x6c/0xd0 fs/super.c:319 deactivate_super fs/super.c:350 [inline] deactivate_super+0x7f/0xa0 fs/super.c:346 cleanup_mnt+0xad/0x140 fs/namespace.c:1183 task_work_run+0x113/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45f497 RSP: 002b:00007fff6e714a38 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000176571 RCX: 000000000045f497 RDX: 00000000004031d8 RSI: 0000000000000002 RDI: 00007fff6e714ae0 RBP: 0000000000001bc7 R08: 0000000000000000 R09: 000000000000000c R10: 0000000000000005 R11: 0000000000000202 R12: 00007fff6e715b70 R13: 0000000002989940 R14: 0000000000000000 R15: 00007fff6e715b70 Showing all locks held in the system: 1 lock held by khungtaskd/1057: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by syz-executor.4/6351: #0: (&type->s_umount_key#64){+.+.}, at: [] deactivate_super fs/super.c:349 [inline] #0: (&type->s_umount_key#64){+.+.}, at: [] deactivate_super+0x77/0xa0 fs/super.c:346 #1: (&type->s_umount_key#47){++++}, at: [] ovl_sync_fs+0xa0/0xe0 fs/overlayfs/super.c:258 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1057 Comm: khungtaskd Not tainted 4.14.182-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6114 Comm: kworker/u4:3 Not tainted 4.14.182-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) task: ffff88809ea98000 task.stack: ffff88820e240000 RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x50 kernel/kcov.c:68 RSP: 0018:ffff88820e247a18 EFLAGS: 00000246 RAX: ffff88809ea98000 RBX: ffff888215474440 RCX: 1ffff1100a5f0b2e RDX: 0000000000000000 RSI: ffff88820e247aa8 RDI: ffff888067389218 RBP: dffffc0000000000 R08: 0000000000000d3e R09: ffffffff89e5b330 R10: ffff88809ea988d8 R11: ffff88809ea98000 R12: ffff8880a18f8b70 R13: ffff88820e247bc0 R14: ffff888215474440 R15: ffff88820e247aa8 FS: 0000000000000000(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f149b4ff4a0 CR3: 0000000007a6a000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: move_expired_inodes+0x294/0x870 fs/fs-writeback.c:1172 queue_io+0x18e/0x4b0 fs/fs-writeback.c:1213 wb_writeback+0x7ed/0xba0 fs/fs-writeback.c:1805 wb_do_writeback fs/fs-writeback.c:1939 [inline] wb_workfn+0x2a8/0xe70 fs/fs-writeback.c:1975 process_one_work+0x7c0/0x14c0 kernel/workqueue.c:2116 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 00 00 e9 be ed ff ff 90 65 48 8b 04 25 40 ee 01 00 48 85 c0 74 1a 65 8b 15 4b 48 a7 7e 81 e2 00 01 1f 00 75 0b 8b 90 58 13 00 00 <83> fa 01 74 01 c3 48 8b 34 24 48 8b 88 60 13 00 00 8b 80 5c 13