md: md1 stopped.
md: md1 stopped.
md: md1 stopped.
md: md1 stopped.
==================================================================
BUG: KASAN: use-after-free in disk_unblock_events+0x42/0x50 block/genhd.c:1647
Read of size 8 at addr ffff8880b05c0f08 by task syz-executor.0/10067

CPU: 0 PID: 10067 Comm: syz-executor.0 Not tainted 4.14.227-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+0x14b/0x1e7 lib/dump_stack.c:58
 print_address_description.cold.6+0x9/0x1ca mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold.7+0x11a/0x2d3 mm/kasan/report.c:393
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 disk_unblock_events+0x42/0x50 block/genhd.c:1647
 __blkdev_get+0x6ef/0xff0 fs/block_dev.c:1556
 blkdev_get+0x265/0x890 fs/block_dev.c:1611
md: md1 stopped.
 blkdev_open+0x19f/0x200 fs/block_dev.c:1772
 do_dentry_open+0x3e4/0xde0 fs/open.c:777
 vfs_open+0xfc/0x240 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0xb6f/0x2760 fs/namei.c:3569
 do_filp_open+0x16b/0x220 fs/namei.c:3603
 do_sys_open+0x1d0/0x350 fs/open.c:1081
 SYSC_openat fs/open.c:1108 [inline]
 SyS_openat+0xf/0x20 fs/open.c:1102
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x465b09
RSP: 002b:00007fc5b8042188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09
RDX: 0000000000000000 RSI: 00000000200020c0 RDI: ffffffffffffff9c
RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008
R13: 00007ffc87d8518f R14: 00007fc5b8042300 R15: 0000000000022000

Allocated by task 10054:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:551
 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:536
 kmem_cache_alloc_node_trace+0x151/0x3f0 mm/slab.c:3661
 kmalloc_node include/linux/slab.h:526 [inline]
 kzalloc_node include/linux/slab.h:672 [inline]
 alloc_disk_node+0x5e/0x380 block/genhd.c:1390
 alloc_disk+0xe/0x10 block/genhd.c:1374
 md_alloc+0x1e0/0x7a0 drivers/md/md.c:5332
 md_probe+0x17/0x20 drivers/md/md.c:5389
 kobj_lookup+0x20a/0x410 drivers/base/map.c:124
 get_gendisk+0x2f/0x1d0 block/genhd.c:788
 __blkdev_get+0x3d4/0xff0 fs/block_dev.c:1449
 blkdev_get+0x265/0x890 fs/block_dev.c:1611
 blkdev_open+0x19f/0x200 fs/block_dev.c:1772
 do_dentry_open+0x3e4/0xde0 fs/open.c:777
 vfs_open+0xfc/0x240 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0xb6f/0x2760 fs/namei.c:3569
 do_filp_open+0x16b/0x220 fs/namei.c:3603
 do_sys_open+0x1d0/0x350 fs/open.c:1081
 SYSC_openat fs/open.c:1108 [inline]
 SyS_openat+0xf/0x20 fs/open.c:1102
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 10067:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xab/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcc/0x270 mm/slab.c:3815
 disk_release+0x215/0x290 block/genhd.c:1233
 device_release+0xd7/0x170 drivers/base/core.c:846
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put lib/kobject.c:692 [inline]
 kobject_put+0x14f/0x3d0 lib/kobject.c:685
 put_disk+0x15/0x20 block/genhd.c:1455
 __blkdev_get+0x65c/0xff0 fs/block_dev.c:1549
 blkdev_get+0x265/0x890 fs/block_dev.c:1611
 blkdev_open+0x19f/0x200 fs/block_dev.c:1772
 do_dentry_open+0x3e4/0xde0 fs/open.c:777
 vfs_open+0xfc/0x240 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0xb6f/0x2760 fs/namei.c:3569
 do_filp_open+0x16b/0x220 fs/namei.c:3603
 do_sys_open+0x1d0/0x350 fs/open.c:1081
 SYSC_openat fs/open.c:1108 [inline]
 SyS_openat+0xf/0x20 fs/open.c:1102
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880b05c0980
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1416 bytes inside of
 2048-byte region [ffff8880b05c0980, ffff8880b05c1180)
The buggy address belongs to the page:
page:ffffea0002c17000 count:1 mapcount:0 mapping:ffff8880b05c0100 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880b05c0100 0000000000000000 0000000100000003
raw: ffffea0002c199a0 ffffea0002536ca0 ffff88813fe64c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b05c0e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880b05c0e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880b05c0f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8880b05c0f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880b05c1000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
md: md1 stopped.