[v5.15] KASAN: use-after-free Read in udf_free_inode (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: aabd761612db Linux 5.15.215
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15995a79580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=f6a0222802ce732a6f6e
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f636f56d3662/disk-aabd7616.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f1a46620f40c/vmlinux-aabd7616.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9b78bb48b022/bzImage-aabd7616.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f6a022...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in le32_add_cpu include/linux/byteorder/generic.h:151 [inline]
BUG: KASAN: use-after-free in udf_free_inode+0x233/0x2a0 fs/udf/ialloc.c:-1
Read of size 4 at addr ffff88809afb3928 by task syz.3.378/5962

CPU: 1 PID: 5962 Comm: syz.3.378 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
print_address_description+0x60/0x2d0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0xdf/0x130 mm/kasan/report.c:451
le32_add_cpu include/linux/byteorder/generic.h:151 [inline]
udf_free_inode+0x233/0x2a0 fs/udf/ialloc.c:-1
evict+0x4b6/0x8b0 fs/inode.c:647
do_unlinkat+0x3e7/0x710 fs/namei.c:4363
__do_sys_unlink fs/namei.c:4404 [inline]
__se_sys_unlink fs/namei.c:4402 [inline]
__x64_sys_unlink+0x45/0x50 fs/namei.c:4402
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa0b72b70d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa0b54ee028 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007fa0b753f090 RCX: 00007fa0b72b70d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000080
RBP: 00007fa0b734e024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa0b753f128 R14: 00007fa0b753f090 R15: 00007ffc14596318
</TASK>

The buggy address belongs to the page:
page:ffffea00026becc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9afb3
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00026becc8 ffffea00026becc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
ffff88809afb3800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88809afb3880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88809afb3900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88809afb3980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88809afb3a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


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