[moderation] [netfilter?] KCSAN: data-race in hash_ipportnet4_add / hash_ipportnet4_head

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 48a5a7ab8d6a Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12ef5ca9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=84b3039e8461eef5
dashboard link: https://syzkaller.appspot.com/bug?extid=fab26bf58136c18f2271
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [core...@netfilter.org da...@davemloft.net edum...@google.com f...@strlen.de ho...@kernel.org ku...@kernel.org linux-...@vger.kernel.org net...@vger.kernel.org netfilt...@vger.kernel.org pab...@redhat.com pa...@netfilter.org ph...@nwl.cc]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f80e802da100/disk-48a5a7ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c52d5cfe5b19/vmlinux-48a5a7ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/117a746cd695/bzImage-48a5a7ab.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fab26b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in hash_ipportnet4_add / hash_ipportnet4_head

read-write to 0xffff88810cb690c8 of 8 bytes by task 3627 on cpu 1:
hash_ipportnet4_add+0x820/0x1590 net/netfilter/ipset/ip_set_hash_gen.h:-1
hash_ipportnet4_uadt+0xb9f/0xd00 net/netfilter/ipset/ip_set_hash_ipportnet.c:291
call_ad+0x231/0x640 net/netfilter/ipset/ip_set_core.c:1758
ip_set_ad+0x5b1/0x680 net/netfilter/ipset/ip_set_core.c:1848
ip_set_uadd+0x41/0x50 net/netfilter/ipset/ip_set_core.c:1871
nfnetlink_rcv_msg+0x4e2/0x5b0 net/netfilter/nfnetlink.c:300
netlink_rcv_skb+0x11e/0x220 net/netlink/af_netlink.c:2556
nfnetlink_rcv+0x15f/0x1740 net/netfilter/nfnetlink.c:667
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x5a7/0x680 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x5be/0x6f0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:775 [inline]
__sock_sendmsg net/socket.c:790 [inline]
____sys_sendmsg+0x532/0x580 net/socket.c:2684
___sys_sendmsg+0x195/0x1e0 net/socket.c:2738
__sys_sendmsg net/socket.c:2770 [inline]
__do_sys_sendmsg net/socket.c:2775 [inline]
__se_sys_sendmsg net/socket.c:2773 [inline]
__x64_sys_sendmsg+0xd4/0x160 net/socket.c:2773
x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810cb690c8 of 8 bytes by task 3629 on cpu 0:
hash_ipportnet4_ext_size net/netfilter/ipset/ip_set_hash_gen.h:860 [inline]
hash_ipportnet4_head+0x340/0x740 net/netfilter/ipset/ip_set_hash_gen.h:1311
ip_set_dump_do+0xa41/0xad0 net/netfilter/ipset/ip_set_core.c:1658
netlink_dump+0x452/0x870 net/netlink/af_netlink.c:2331
netlink_recvmsg+0x420/0x550 net/netlink/af_netlink.c:1982
sock_recvmsg_nosec net/socket.c:1126 [inline]
sock_recvmsg+0xf5/0x120 net/socket.c:1148
____sys_recvmsg+0xf5/0x280 net/socket.c:2904
___sys_recvmsg+0x11f/0x3a0 net/socket.c:2946
__sys_recvmsg net/socket.c:2979 [inline]
__do_sys_recvmsg net/socket.c:2985 [inline]
__se_sys_recvmsg net/socket.c:2982 [inline]
__x64_sys_recvmsg+0xd1/0x160 net/socket.c:2982
x64_sys_call+0x2b1a/0x3020 arch/x86/include/generated/asm/syscalls_64.h:48
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000001dea0 -> 0x000000000001df10

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3629 Comm: syz.4.48 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
==================================================================


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