[syzbot] [net?] upstream test error: KMSAN: use-after-free in mctp_dump_addrinfo

[syzbot <syzbot+1065a199625a388fce60@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    4f79eaa2ceac kbuild: Properly disable -Wunterminated-strin..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15bc71b3980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=53c85d265a8f3692
dashboard link: https://syzkaller.appspot.com/bug?extid=1065a199625a388fce60
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/3594998c29f0/disk-4f79eaa2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2cd908ac5281/vmlinux-4f79eaa2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5ea15b7bacde/bzImage-4f79eaa2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1065a199625a388fce60@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: use-after-free 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_free_hook mm/slub.c:2324 [inline]
 slab_free mm/slub.c:4656 [inline]
 kmem_cache_free+0x286/0xf00 mm/slub.c:4758
 skb_kfree_head net/core/skbuff.c:1056 [inline]
 skb_free_head net/core/skbuff.c:1070 [inline]
 skb_release_data+0xe56/0x1110 net/core/skbuff.c:1097
 skb_release_all net/core/skbuff.c:1162 [inline]
 __kfree_skb+0x6b/0x260 net/core/skbuff.c:1176
 consume_skb+0x83/0x230 net/core/skbuff.c:1408
 netlink_broadcast_filtered+0x21b6/0x2370 net/netlink/af_netlink.c:1524
 nlmsg_multicast_filtered include/net/netlink.h:1129 [inline]
 nlmsg_multicast include/net/netlink.h:1148 [inline]
 nlmsg_notify+0x15b/0x2f0 net/netlink/af_netlink.c:2577
 rtnl_notify+0xba/0x100 net/core/rtnetlink.c:958
 inet6_rt_notify+0x27d/0x4a0 net/ipv6/route.c:6270
 fib6_add_rt2node net/ipv6/ip6_fib.c:1259 [inline]
 fib6_add+0x33c7/0x6c70 net/ipv6/ip6_fib.c:1488
 __ip6_ins_rt net/ipv6/route.c:1351 [inline]
 ip6_ins_rt+0xc0/0x170 net/ipv6/route.c:1361
 __ipv6_ifa_notify+0x851/0x1990 net/ipv6/addrconf.c:6283
 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline]
 add_addr+0x301/0x4c0 net/ipv6/addrconf.c:3206
 init_loopback net/ipv6/addrconf.c:3289 [inline]
 addrconf_init_auto_addrs+0xb53/0x10e0 net/ipv6/addrconf.c:3564
 addrconf_notify+0x1643/0x1d10 net/ipv6/addrconf.c:3741
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0xdd/0x410 kernel/notifier.c:453
 call_netdevice_notifiers_info+0x1ac/0x2b0 net/core/dev.c:2176
 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
 call_netdevice_notifiers net/core/dev.c:2228 [inline]
 __dev_notify_flags+0x20d/0x3c0 net/core/dev.c:-1
 netif_change_flags+0x162/0x1e0 net/core/dev.c:9434
 dev_change_flags+0x18c/0x320 net/core/dev_api.c:68
 devinet_ioctl+0x1186/0x2500 net/ipv4/devinet.c:1200
 inet_ioctl+0x4c0/0x6f0 net/ipv4/af_inet.c:1001
 sock_do_ioctl+0x9c/0x480 net/socket.c:1190
 sock_ioctl+0x70b/0xd60 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0x239/0x400 fs/ioctl.c:892
 __x64_sys_ioctl+0x97/0xe0 fs/ioctl.c:892
 x64_sys_call+0x1ebe/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:17
 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: 1 UID: 0 PID: 5440 Comm: dhcpcd Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
=====================================================


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