Buffer I/O error on dev loop5p2, logical block 0, async page read print_req_error: I/O error, dev loop5, sector 0 Buffer I/O error on dev loop5p2, logical block 0, async page read loop_reread_partitions: partition scan of loop5 () failed (rc=-16) INFO: task syz-executor.0:12301 blocked for more than 140 seconds. Not tainted 4.14.270-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29824 12301 7984 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 __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 blkdev_flushbuf block/ioctl.c:430 [inline] blkdev_ioctl+0x883/0x1830 block/ioctl.c:514 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: 0033:0x7f1b3fcbd049 RSP: 002b:00007f1b3e632168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1b3fdcff60 RCX: 00007f1b3fcbd049 RDX: 0000000000000000 RSI: 0000000000001261 RDI: 0000000000000003 RBP: 00007f1b3fd1708d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc5488fe2f R14: 00007f1b3e632300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1533: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by syz-executor.0/12301: #0: (&type->s_umount_key#65){.+.+}, at: [] __get_super.part.0+0x271/0x390 fs/super.c:678 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1533 Comm: khungtaskd Not tainted 4.14.270-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+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 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: 12308 Comm: syz-executor.0 Not tainted 4.14.270-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88808bb8a1c0 task.stack: ffff888055ec0000 RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x50 kernel/kcov.c:65 RSP: 0018:ffff888055ec76a8 EFLAGS: 00000246 RAX: ffff88808bb8a1c0 RBX: ffffea0002bdc2c0 RCX: 1ffff1101177154e RDX: 1ffffd400057b85c RSI: 0000000000000002 RDI: ffffea0002bdc2c0 RBP: ffffea0002bdc2e0 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: ffff88808bb8a1c0 R12: ffffea0002bdc2c0 R13: ffffea00026ca4e0 R14: dffffc0000000000 R15: 0000000000000001 FS: 00007f1b3e611700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc982551000 CR3: 000000009a395000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] PageActive include/linux/page-flags.h:274 [inline] mark_page_accessed+0x73/0x530 mm/swap.c:379 pagecache_get_page+0x40a/0xab0 mm/filemap.c:1491 find_get_page_flags include/linux/pagemap.h:282 [inline] __find_get_block_slow fs/buffer.c:214 [inline] __find_get_block+0x4cc/0xc40 fs/buffer.c:1357 __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] udf_tread+0xe1/0x130 fs/udf/misc.c:44 udf_read_tagged+0x40/0x4c0 fs/udf/misc.c:219 udf_check_anchor_block+0x18a/0x590 fs/udf/super.c:1823 udf_scan_anchors+0x321/0x530 fs/udf/super.c:1885 udf_find_anchor fs/udf/super.c:1920 [inline] udf_load_vrs+0x5a1/0xa90 fs/udf/super.c:1985 udf_fill_super+0x715/0x1660 fs/udf/super.c:2177 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:2572 [inline] do_mount+0xe65/0x2a10 fs/namespace.c:2902 SYSC_mount fs/namespace.c:3118 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3095 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f1b3fcbd049 RSP: 002b:00007f1b3e611168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f1b3fdd0030 RCX: 00007f1b3fcbd049 RDX: 0000000020000040 RSI: 0000000020000280 RDI: 00000000200004c0 RBP: 00007f1b3fd1708d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc5488fe2f R14: 00007f1b3e611300 R15: 0000000000022000 Code: 00 e9 9f fe ff ff 4c 89 e7 e8 04 b1 29 00 e9 2c fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 c0 7f 02 00 <48> 85 c0 74 1a 65 8b 15 0b 3d ad 7e 81 e2 00 01 1f 00 75 0b 8b ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e9 9f fe ff ff jmpq 0xfffffea4 5: 4c 89 e7 mov %r12,%rdi 8: e8 04 b1 29 00 callq 0x29b111 d: e9 2c fe ff ff jmpq 0xfffffe3e 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 65 48 8b 04 25 c0 7f mov %gs:0x27fc0,%rax 28: 02 00 * 2a: 48 85 c0 test %rax,%rax <-- trapping instruction 2d: 74 1a je 0x49 2f: 65 8b 15 0b 3d ad 7e mov %gs:0x7ead3d0b(%rip),%edx # 0x7ead3d41 36: 81 e2 00 01 1f 00 and $0x1f0100,%edx 3c: 75 0b jne 0x49 3e: 8b .byte 0x8b