batman_adv: batadv0: Interface activated: batadv_slave_1
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
==================================================================
BUG: KASAN: use-after-free in disk_unblock_events+0x42/0x50 block/genhd.c:1644
Read of size 8 at addr ffff8880a8d989c8 by task systemd-udevd/3636

CPU: 0 PID: 3636 Comm: systemd-udevd Not tainted 4.14.202-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+0xf7/0x13b lib/dump_stack.c:58
 print_address_description.cold.7+0x9/0x1c9 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report.cold.8+0x11a/0x2d3 mm/kasan/report.c:409
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 disk_unblock_events+0x42/0x50 block/genhd.c:1644
 __blkdev_get+0x6bd/0x1020 fs/block_dev.c:1556
 blkdev_get+0x265/0x890 fs/block_dev.c:1611
 blkdev_open+0x19f/0x200 fs/block_dev.c:1772
 do_dentry_open+0x620/0xdb0 fs/open.c:777
 vfs_open+0xfc/0x240 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0xdde/0x3bd0 fs/namei.c:3569
 do_filp_open+0x16b/0x220 fs/namei.c:3603
 do_sys_open+0x1c2/0x340 fs/open.c:1081
 SYSC_open fs/open.c:1099 [inline]
 SyS_open+0x19/0x20 fs/open.c:1094
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7fa7cbbf1840
RSP: 002b:00007fffa9d45308 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fffa9d453a0 RCX: 00007fa7cbbf1840
RDX: 000055ee51032fe3 RSI: 00000000000a0800 RDI: 000055ee52cdb760
RBP: 00007fffa9d45900 R08: 000055ee51032670 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffa9d454b0
R13: 000055ee52c17a60 R14: 000055ee52cfae40 R15: 00007fffa9d45380

Allocated by task 8958:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:551
 kmem_cache_alloc_node_trace+0x14c/0x780 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:1387
 alloc_disk+0xe/0x10 block/genhd.c:1371
 loop_add+0x3a9/0x810 drivers/block/loop.c:1869
 loop_probe+0x133/0x160 drivers/block/loop.c:1976
 kobj_lookup+0x20a/0x410 drivers/base/map.c:124
 get_gendisk+0x2d/0x1d0 block/genhd.c:785
 __blkdev_get+0x382/0x1020 fs/block_dev.c:1449
 blkdev_get+0x417/0x890 fs/block_dev.c:1611
 blkdev_open+0x19f/0x200 fs/block_dev.c:1772
 do_dentry_open+0x620/0xdb0 fs/open.c:777
 vfs_open+0xfc/0x240 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0xdde/0x3bd0 fs/namei.c:3569
 do_filp_open+0x16b/0x220 fs/namei.c:3603
 do_sys_open+0x1c2/0x340 fs/open.c:1081
 SYSC_open fs/open.c:1099 [inline]
 SyS_open+0x19/0x20 fs/open.c:1094
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 3636:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 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:3496 [inline]
 kfree+0xcc/0x270 mm/slab.c:3815
 disk_release+0x215/0x290 block/genhd.c:1230
 device_release+0xd7/0x170 drivers/base/core.c:831
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x10d/0x1b0 lib/kobject.c:692
 put_disk+0x15/0x20 block/genhd.c:1452
 __blkdev_get+0x62a/0x1020 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+0x620/0xdb0 fs/open.c:777
 vfs_open+0xfc/0x240 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0xdde/0x3bd0 fs/namei.c:3569
 do_filp_open+0x16b/0x220 fs/namei.c:3603
 do_sys_open+0x1c2/0x340 fs/open.c:1081
 SYSC_open fs/open.c:1099 [inline]
 SyS_open+0x19/0x20 fs/open.c:1094
 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 ffff8880a8d98440
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1416 bytes inside of
 2048-byte region [ffff8880a8d98440, ffff8880a8d98c40)
The buggy address belongs to the page:
page:ffffea0002a36600 count:1 mapcount:0 mapping:ffff8880a8d98440 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a8d98440 0000000000000000 0000000100000003
raw: ffffea00020a02a0 ffffea0002a7eca0 ffff8880aa800c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a8d98880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a8d98900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a8d98980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8880a8d98a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a8d98a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================