netlink: 3 bytes leftover after parsing attributes in process `syz-executor7'.
==================================================================
BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 block/genhd.c:1654
Read of size 8 at addr ffff8801cb341c30 by task syz-executor1/17926
CPU: 0 PID: 17926 Comm: syz-executor1 Not tainted 4.14.0-mm1+ #25
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+0x194/0x257 lib/dump_stack.c:53
print_address_description+0x73/0x250 mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report+0x25b/0x340 mm/kasan/report.c:409
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
disk_unblock_events+0x51/0x60 block/genhd.c:1654
__blkdev_get+0x869/0x10e0 fs/block_dev.c:1535
blkdev_get+0x3a1/0xad0 fs/block_dev.c:1591
blkdev_open+0x1e4/0x270 fs/block_dev.c:1749
do_dentry_open+0x682/0xd70 fs/open.c:752
vfs_open+0x107/0x230 fs/open.c:866
do_last fs/namei.c:3388 [inline]
path_openat+0x1157/0x3530 fs/namei.c:3528
do_filp_open+0x25b/0x3b0 fs/namei.c:3563
do_sys_open+0x502/0x6d0 fs/open.c:1059
SYSC_open fs/open.c:1077 [inline]
SyS_open+0x2d/0x40 fs/open.c:1072
entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x40cbb1
RSP: 002b:00007f8246b16710 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: cccccccccccccccd RCX: 000000000040cbb1
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007f8246b167c0
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000c R11: 0000000000000293 R12: 00000000006f5590
R13: 00000000ffffffff R14: 00007f8246b176d4 R15: 0000000000000004
Allocated by task 17926:
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
kmem_cache_alloc_node_trace+0x150/0x760 mm/slab.c:3657
kmalloc_node include/linux/slab.h:552 [inline]
kzalloc_node include/linux/slab.h:714 [inline]
__alloc_disk_node+0xb4/0x4e0 block/genhd.c:1397
loop_add+0x44c/0xa70 drivers/block/loop.c:1808
loop_probe+0x16d/0x1a0 drivers/block/loop.c:1915
kobj_lookup+0x2ac/0x410 drivers/base/map.c:124
get_gendisk+0x37/0x2c0 block/genhd.c:786
__blkdev_get+0x3ea/0x10e0 fs/block_dev.c:1433
blkdev_get+0x3a1/0xad0 fs/block_dev.c:1591
blkdev_open+0x1e4/0x270 fs/block_dev.c:1749
do_dentry_open+0x682/0xd70 fs/open.c:752
vfs_open+0x107/0x230 fs/open.c:866
do_last fs/namei.c:3388 [inline]
path_openat+0x1157/0x3530 fs/namei.c:3528
do_filp_open+0x25b/0x3b0 fs/namei.c:3563
do_sys_open+0x502/0x6d0 fs/open.c:1059
SYSC_open fs/open.c:1077 [inline]
SyS_open+0x2d/0x40 fs/open.c:1072
entry_SYSCALL_64_fastpath+0x1f/0x96
Freed by task 17926:
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
__cache_free mm/slab.c:3492 [inline]
kfree+0xca/0x250 mm/slab.c:3807
disk_release+0x327/0x410 block/genhd.c:1246
device_release+0x7c/0x210 drivers/base/core.c:814
kobject_cleanup lib/kobject.c:648 [inline]
kobject_release lib/kobject.c:677 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put+0x14c/0x250 lib/kobject.c:694
put_disk+0x23/0x30 block/genhd.c:1462
__blkdev_get+0x7c9/0x10e0 fs/block_dev.c:1528
blkdev_get+0x3a1/0xad0 fs/block_dev.c:1591
blkdev_open+0x1e4/0x270 fs/block_dev.c:1749
do_dentry_open+0x682/0xd70 fs/open.c:752
vfs_open+0x107/0x230 fs/open.c:866
do_last fs/namei.c:3388 [inline]
path_openat+0x1157/0x3530 fs/namei.c:3528
do_filp_open+0x25b/0x3b0 fs/namei.c:3563
do_sys_open+0x502/0x6d0 fs/open.c:1059
SYSC_open fs/open.c:1077 [inline]
SyS_open+0x2d/0x40 fs/open.c:1072
entry_SYSCALL_64_fastpath+0x1f/0x96
The buggy address belongs to the object at ffff8801cb341600
which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1584 bytes inside of
2048-byte region [ffff8801cb341600, ffff8801cb341e00)
The buggy address belongs to the page:
page:ffffea00072cd000 count:1 mapcount:0 mapping:ffff8801cb340500 index:0xffff8801cb340500 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801cb340500 ffff8801cb340500 0000000100000001
raw: ffffea00074b3b20 ffffea00070c1020 ffff8801db000c40 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801cb341b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801cb341b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801cb341c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801cb341c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801cb341d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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