[syzbot] [net?] upstream test error: KMSAN: uninit-value in mctp_dump_addrinfo

[syzbot <syzbot+e76d52dadc089b9d197f@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    b4432656b36e Linux 6.15-rc4
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=173ea374580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f944a52db88df992
dashboard link: https://syzkaller.appspot.com/bug?extid=e76d52dadc089b9d197f
compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/26fcd648d1b5/disk-b4432656.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/25ce9039317e/vmlinux-b4432656.xz
kernel image: https://storage.googleapis.com/syzbot-assets/387f0baa5e6e/bzImage-b4432656.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e76d52dadc089b9d197f@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in mctp_dump_addrinfo+0x208/0xac0 net/mctp/device.c:128
 mctp_dump_addrinfo+0x208/0xac0 net/mctp/device.c:128
 rtnl_dump_all+0x3ec/0x5b0 net/core/rtnetlink.c:4380
 rtnl_dumpit+0xd5/0x2f0 net/core/rtnetlink.c:6824
 netlink_dump+0x97b/0x1690 net/netlink/af_netlink.c:2309
 __netlink_dump_start+0x716/0xd60 net/netlink/af_netlink.c:2424
 netlink_dump_start include/linux/netlink.h:340 [inline]
 rtnetlink_dump_start net/core/rtnetlink.c:6853 [inline]
 rtnetlink_rcv_msg+0x1262/0x14b0 net/core/rtnetlink.c:6920
 netlink_rcv_skb+0x54a/0x680 net/netlink/af_netlink.c:2534
 rtnetlink_rcv+0x35/0x40 net/core/rtnetlink.c:6982
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0xed5/0x1290 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x10b3/0x1250 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x330/0x3d0 net/socket.c:727
 __sys_sendto+0x590/0x710 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0x130/0x200 net/socket.c:2183
 x64_sys_call+0x3c0b/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4167 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4262
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:577
 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1340 [inline]
 netlink_alloc_large_skb+0xa5/0x280 net/netlink/af_netlink.c:1187
 netlink_sendmsg+0xaea/0x1250 net/netlink/af_netlink.c:1858
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x330/0x3d0 net/socket.c:727
 __sys_sendto+0x590/0x710 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0x130/0x200 net/socket.c:2183
 x64_sys_call+0x3c0b/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5447 Comm: dhcpcd Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup