[v6.1] KASAN: slab-out-of-bounds Read in lmWriteRecord

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f6e38ae624cf Linux 6.1.158
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15957e12580000
kernel config: https://syzkaller.appspot.com/x/.config?x=68aa5a3af1cb953a
dashboard link: https://syzkaller.appspot.com/bug?extid=b6bfcb2c90eb2e0abded
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c1bd671a9def/disk-f6e38ae6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fa0af998ea40/vmlinux-f6e38ae6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e5512d873524/Image-f6e38ae6.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6bfcb...@syzkaller.appspotmail.com

loop3: detected capacity change from 0 to 32768
UFO tlock:0x00000000c64e1c8b
UFO tlock:0x000000000017bcdc
==================================================================
BUG: KASAN: slab-out-of-bounds in lmWriteRecord+0x3c4/0x15d4 fs/jfs/jfs_logmgr.c:425
Read of size 32 at addr ffff0000dcc892e0 by task syz.3.693/7428

CPU: 0 PID: 7428 Comm: syz.3.693 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack+0x30/0x40 lib/dump_stack.c:88
dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
print_address_description+0x88/0x218 mm/kasan/report.c:316
print_report+0x50/0x68 mm/kasan/report.c:420
kasan_report+0xa8/0x100 mm/kasan/report.c:524
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x260/0x2a0 mm/kasan/generic.c:189
memcpy+0x48/0x90 mm/kasan/shadow.c:65
lmWriteRecord+0x3c4/0x15d4 fs/jfs/jfs_logmgr.c:425
lmLog+0x57c/0x850 fs/jfs/jfs_logmgr.c:314
dtLog fs/jfs/jfs_txnmgr.c:1618 [inline]
txLog fs/jfs/jfs_txnmgr.c:1400 [inline]
txCommit+0x13d8/0x3bec fs/jfs/jfs_txnmgr.c:1264
jfs_mkdir+0x6e4/0x8b4 fs/jfs/namei.c:290
vfs_mkdir+0x314/0x4d4 fs/namei.c:4114
do_mkdirat+0x1b4/0x3e0 fs/namei.c:4139
__do_sys_mkdirat fs/namei.c:4154 [inline]
__se_sys_mkdirat fs/namei.c:4152 [inline]
__arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4152
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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:585

Allocated by task 7042:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
kasan_save_alloc_info+0x28/0x34 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:383
kasan_kmalloc include/linux/kasan.h:211 [inline]
kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
snmp6_alloc_dev net/ipv6/addrconf.c:350 [inline]
ipv6_add_dev+0x494/0xee4 net/ipv6/addrconf.c:404
addrconf_notify+0x518/0xca8 net/ipv6/addrconf.c:3595
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
call_netdevice_notifiers_info net/core/dev.c:2001 [inline]
call_netdevice_notifiers_extack net/core/dev.c:2039 [inline]
call_netdevice_notifiers+0x10c/0x18c net/core/dev.c:2053
register_netdevice+0x1188/0x15cc net/core/dev.c:10237
veth_newlink+0x62c/0xa24 drivers/net/veth.c:1756
rtnl_newlink_create net/core/rtnetlink.c:3422 [inline]
__rtnl_newlink net/core/rtnetlink.c:3642 [inline]
rtnl_newlink+0x102c/0x1a1c net/core/rtnetlink.c:3655
rtnetlink_rcv_msg+0x734/0xce4 net/core/rtnetlink.c:6150
netlink_rcv_skb+0x208/0x3c4 net/netlink/af_netlink.c:2511
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6168
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x60c/0x824 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x6e8/0x9b0 net/netlink/af_netlink.c:1872
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
__sys_sendto+0x304/0x3fc net/socket.c:2153
__do_sys_sendto net/socket.c:2165 [inline]
__se_sys_sendto net/socket.c:2161 [inline]
__arm64_sys_sendto+0xd8/0xf8 net/socket.c:2161
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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:585

The buggy address belongs to the object at ffff0000dcc89200
which belongs to the cache kmalloc-128 of size 128
The buggy address is located 96 bytes to the right of
128-byte region [ffff0000dcc89200, ffff0000dcc89280)

The buggy address belongs to the physical page:
page:000000005cb3ccce refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11cc89
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 dead000000000100 dead000000000122 ffff0000c0002300
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000dcc89180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000dcc89200: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
>ffff0000dcc89280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff0000dcc89300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff0000dcc89380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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