[v6.1] KASAN: use-after-free Read in reiserfs_get_unused_objectid

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e3a87a10f259 Linux 6.1.21
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13d327b1c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=390800ef8aeebc47
dashboard link: https://syzkaller.appspot.com/bug?extid=259aeff26243c6d99769
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=177804b6c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e54b89c80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9f5022ccd560/disk-e3a87a10.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f8524664c631/vmlinux-e3a87a10.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ad699b30c2c4/Image-e3a87a10.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/7457a7ed2162/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+259aef...@syzkaller.appspotmail.com

REISERFS (device loop0): journal params: device loop0, size 512, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using r5 hash to sort names
==================================================================
BUG: KASAN: use-after-free in reiserfs_get_unused_objectid+0x1c4/0x3bc fs/reiserfs/objectid.c:87
Read of size 250888 at addr ffff0000e0104058 by task syz-executor356/4316

CPU: 0 PID: 4316 Comm: syz-executor356 Not tainted 6.1.21-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:284 [inline]
print_report+0x174/0x4c0 mm/kasan/report.c:395
kasan_report+0xd4/0x130 mm/kasan/report.c:495
kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189
memmove+0x48/0x90 mm/kasan/shadow.c:54
reiserfs_get_unused_objectid+0x1c4/0x3bc fs/reiserfs/objectid.c:87
reiserfs_new_inode+0x238/0x1724 fs/reiserfs/inode.c:1944
reiserfs_mkdir+0x4ac/0x77c fs/reiserfs/namei.c:845
xattr_mkdir fs/reiserfs/xattr.c:76 [inline]
create_privroot fs/reiserfs/xattr.c:882 [inline]
reiserfs_xattr_init+0x2b0/0x6bc fs/reiserfs/xattr.c:1005
reiserfs_fill_super+0x1bfc/0x2028 fs/reiserfs/super.c:2175
mount_bdev+0x26c/0x368 fs/super.c:1414
get_super_block+0x44/0x58 fs/reiserfs/super.c:2601
legacy_get_tree+0xd4/0x16c fs/fs_context.c:610
vfs_get_tree+0x90/0x274 fs/super.c:1544
do_new_mount+0x25c/0x8c8 fs/namespace.c:3040
path_mount+0x590/0xe58 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__arm64_sys_mount+0x45c/0x594 fs/namespace.c:3568
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

The buggy address belongs to the physical page:
page:000000001b38b64e refcount:3 mapcount:0 mapping:000000005de5117f index:0x10 pfn:0x120104
memcg:ffff0000c0930000
aops:def_blk_aops ino:700000
flags: 0x5ffc20000002042(referenced|workingset|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc20000002042 0000000000000000 dead000000000122 ffff0000c0481310
raw: 0000000000000010 ffff0000dd1e5740 00000003ffffffff ffff0000c0930000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000e0107f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff0000e0107f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000e0108000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff0000e0108080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff0000e0108100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
REISERFS warning: reiserfs-5093 is_leaf: item entry count seems wrong *3.5*[2 1 0(1) DIR], item_len 35, item_location 3985, free_space(entry_count) 2
REISERFS error (device loop0): vs-5150 search_by_key: invalid format found in block 531. Fsck?
REISERFS (device loop0): Remounting filesystem read-only
REISERFS error (device loop0): vs-13050 reiserfs_update_sd_size: i/o failure occurred trying to update [2 1 0x0 SD] stat data
REISERFS warning: reiserfs-5093 is_leaf: item entry count seems wrong *3.5*[2 1 0(1) DIR], item_len 35, item_location 3985, free_space(entry_count) 2
REISERFS error (device loop0): vs-5150 search_by_key: invalid format found in block 531. Fsck?
REISERFS error (device loop0): zam-7001 reiserfs_find_entry: io error
REISERFS warning: reiserfs-5093 is_leaf: item entry count seems wrong *3.5*[2 1 0(1) DIR], item_len 35, item_location 3985, free_space(entry_count) 2
REISERFS error (device loop0): vs-5150 search_by_key: invalid format found in block 531. Fsck?
REISERFS error (device loop0): vs-13050 reiserfs_update_sd_size: i/o failure occurred trying to update [2 1 0x0 SD] stat data
REISERFS warning (device loop0): jdm-20006 create_privroot: xattrs/ACLs enabled and couldn't find/create .reiserfs_priv. Failing mount.


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