KASAN: use-after-free Read in exact_lock

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a8aad8851131 ANDROID: GKI: enable mulitcolor-led
git tree: android12-5.4
console output: https://syzkaller.appspot.com/x/log.txt?x=121652df880000
kernel config: https://syzkaller.appspot.com/x/.config?x=b4f7fdc1fca3154e
dashboard link: https://syzkaller.appspot.com/bug?extid=6f4057150d2690daf09f
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/71fa3d1afcd2/disk-a8aad885.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6d25e2985873/vmlinux-a8aad885.xz
kernel image: https://storage.googleapis.com/syzbot-assets/97866ff1e151/bzImage-a8aad885.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6f4057...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in get_disk_and_module block/genhd.c:1524 [inline]
BUG: KASAN: use-after-free in exact_lock+0x34/0xc0 block/genhd.c:594
Read of size 8 at addr ffff8881f0ef14d0 by task udevd/17156

CPU: 0 PID: 17156 Comm: udevd Tainted: G W 5.4.219-syzkaller-00012-ga8aad8851131 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1d8/0x241 lib/dump_stack.c:118
print_address_description+0x8c/0x630 mm/kasan/report.c:384
__kasan_report+0xf6/0x130 mm/kasan/report.c:516
kasan_report+0x30/0x60 mm/kasan/common.c:653
get_disk_and_module block/genhd.c:1524 [inline]
exact_lock+0x34/0xc0 block/genhd.c:594
kobj_lookup+0x2bb/0x460 drivers/base/map.c:119
get_gendisk+0xd6/0x370 block/genhd.c:879
bdev_get_gendisk fs/block_dev.c:1105 [inline]
__blkdev_get+0x155/0x1780 fs/block_dev.c:1560
blkdev_get+0x2d8/0x3a0 fs/block_dev.c:1714
do_dentry_open+0x946/0x10f0 fs/open.c:796
do_last fs/namei.c:3495 [inline]
path_openat+0x1603/0x3ea0 fs/namei.c:3614
do_filp_open+0x208/0x450 fs/namei.c:3644
do_sys_open+0x393/0x7e0 fs/open.c:1113
do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Allocated by task 21885:
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
__kasan_kmalloc+0x131/0x1e0 mm/kasan/common.c:529
kmalloc include/linux/slab.h:561 [inline]
sk_prot_alloc+0xbc/0x3c0 net/core/sock.c:1618
sk_alloc+0x30/0x390 net/core/sock.c:1676
__netlink_create net/netlink/af_netlink.c:636 [inline]
netlink_create+0x3b7/0x620 net/netlink/af_netlink.c:699
__sock_create+0x393/0x730 net/socket.c:1408
sock_create net/socket.c:1459 [inline]
__sys_socket+0x133/0x370 net/socket.c:1501
__do_sys_socket net/socket.c:1510 [inline]
__se_sys_socket net/socket.c:1508 [inline]
__x64_sys_socket+0x76/0x80 net/socket.c:1508
do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 321:
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
kasan_set_free_info mm/kasan/common.c:345 [inline]
__kasan_slab_free+0x178/0x240 mm/kasan/common.c:487
slab_free_hook mm/slub.c:1455 [inline]
slab_free_freelist_hook+0x80/0x150 mm/slub.c:1494
slab_free mm/slub.c:3080 [inline]
kfree+0xc6/0x260 mm/slub.c:4071
sk_prot_free+0xa3/0x160 net/core/sock.c:1659
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch+0x49e/0xa10 kernel/rcu/tree.c:2167
rcu_core+0x4ba/0xca0 kernel/rcu/tree.c:2387
__do_softirq+0x23e/0x643 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881f0ef1000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1232 bytes inside of
2048-byte region [ffff8881f0ef1000, ffff8881f0ef1800)
The buggy address belongs to the page:
page:ffffea0007c3bc00 refcount:1 mapcount:0 mapping:ffff8881f5c0c000 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c0c000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL)
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook mm/page_alloc.c:2165 [inline]
prep_new_page+0x194/0x380 mm/page_alloc.c:2171
get_page_from_freelist+0x524/0x560 mm/page_alloc.c:3794
__alloc_pages_nodemask+0x372/0x860 mm/page_alloc.c:4891
alloc_slab_page+0x39/0x3e0 mm/slub.c:343
allocate_slab mm/slub.c:1683 [inline]
new_slab+0x97/0x450 mm/slub.c:1749
new_slab_objects mm/slub.c:2505 [inline]
___slab_alloc+0x320/0x4a0 mm/slub.c:2667
__slab_alloc+0x5a/0x90 mm/slub.c:2707
slab_alloc_node mm/slub.c:2792 [inline]
slab_alloc mm/slub.c:2837 [inline]
kmem_cache_alloc_trace+0x129/0x240 mm/slub.c:2854
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:690 [inline]
alloc_super+0x56/0x750 fs/super.c:203
sget_fc+0x247/0x650 fs/super.c:530
vfs_get_super fs/super.c:1186 [inline]
get_tree_nodev+0x26/0x150 fs/super.c:1221
vfs_get_tree+0x85/0x260 fs/super.c:1547
fc_mount fs/namespace.c:962 [inline]
vfs_kern_mount+0xc6/0x160 fs/namespace.c:992
kern_mount+0x3f/0x90 fs/namespace.c:3812
aio_setup+0x11/0x8a fs/aio.c:274
do_one_initcall+0x1b5/0x6d0 init/main.c:1203
page_owner free stack trace missing

Memory state around the buggy address:
ffff8881f0ef1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881f0ef1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881f0ef1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881f0ef1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881f0ef1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
udevd[17156]: inotify_add_watch(7, /dev/loop0, 10) failed: No such file or directory


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.