EXT4-fs warning (device loop5): ext4_rmdir:3021: inode #12: comm syz-executor.5: empty directory 'file0' has too many links (23764) EXT4-fs error (device loop5): ext4_free_inode:353: comm syz-executor.5: bit already cleared for inode 12 INFO: task syz-executor.2:27814 blocked for more than 140 seconds. Not tainted 4.14.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28960 27814 27809 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x1e6/0x350 kernel/locking/rwsem-xadd.c:309 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:66 [inline] down_read+0x44/0x80 kernel/locking/rwsem.c:26 __get_super.part.0+0x271/0x390 fs/super.c:678 __get_super include/linux/spinlock.h:317 [inline] get_super+0x2b/0x50 fs/super.c:707 fsync_bdev+0x14/0xc0 fs/block_dev.c:495 invalidate_partition+0x74/0xb0 block/genhd.c:1506 drop_partitions.isra.0+0x83/0x150 block/partition-generic.c:442 rescan_partitions+0xa9/0x800 block/partition-generic.c:515 __blkdev_reread_part+0x140/0x1d0 block/ioctl.c:173 blkdev_reread_part+0x23/0x40 block/ioctl.c:193 loop_reread_partitions drivers/block/loop.c:624 [inline] loop_set_status+0xeeb/0x12b0 drivers/block/loop.c:1193 loop_set_status64+0x92/0xe0 drivers/block/loop.c:1311 lo_ioctl+0x587/0x1cd0 drivers/block/loop.c:1441 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45dd27 RSP: 002b:00007f86a66d09f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045dd27 RDX: 00007f86a66d0ac0 RSI: 0000000000004c04 RDI: 0000000000000006 RBP: 000000000118bf60 R08: 00007f86a66d0a28 R09: 0000000000000000 R10: 00007f86a66d0a2c R11: 0000000000000202 R12: 000000000118bf2c R13: 00007ffea21b304f R14: 00007f86a66d19c0 R15: 000000000118bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1530: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 3 locks held by syz-executor.2/27814: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#82){.+.+}, at: [] __get_super.part.0+0x271/0x390 fs/super.c:678 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1530 Comm: khungtaskd Not tainted 4.14.204-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+0x5b9/0xb40 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: 27809 Comm: syz-executor.2 Not tainted 4.14.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809a67a4c0 task.stack: ffff8880abfc8000 RIP: 0010:__sanitizer_cov_trace_pc+0x3d/0x50 kernel/kcov.c:87 RSP: 0018:ffff8880abfcfb20 EFLAGS: 00000246 RAX: 0000000000040000 RBX: 0000000000000001 RCX: ffffc900082d5000 RDX: 000000000003ffff RSI: ffffffff81950c20 RDI: ffff8880a60621c0 RBP: ffffea0001ad7f9c R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: ffff88809a67a4c0 R12: 0000000000000200 R13: 0000000000000200 R14: 0000000000000001 R15: dffffc0000000000 FS: 00007f86a66d1700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f174d463000 CR3: 000000008d3e7000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_local_save_flags arch/x86/include/asm/paravirt.h:774 [inline] check_irqs_on fs/buffer.c:1280 [inline] lookup_bh_lru fs/buffer.c:1321 [inline] __find_get_block+0x50/0xc40 fs/buffer.c:1353 __getblk_slow+0x127/0x7a0 fs/buffer.c:1100 __getblk_gfp fs/buffer.c:1383 [inline] __bread_gfp+0x206/0x2e0 fs/buffer.c:1428 sb_bread include/linux/buffer_head.h:309 [inline] efs_fill_super+0x3dc/0xac0 fs/efs/super.c:294 mount_bdev+0x2b3/0x360 fs/super.c:1134 mount_fs+0x92/0x2a0 fs/super.c:1237 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0xe53/0x2a00 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3072 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45deb9 RSP: 002b:00007f86a66d0c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00000000000217c0 RCX: 000000000045deb9 RDX: 0000000020000400 RSI: 00000000200001c0 RDI: 0000000020000240 RBP: 000000000118bf70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffea21b304f R14: 00007f86a66d19c0 R15: 000000000118bf2c Code: a0 aa 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 00 00 48 8b 11 <48> 83 c2 01 48 39 d0 76 e2 48 89 34 d1 48 89 11 c3 66 90 41 54