CVE-2026-52975

In the Linux kernel, the following vulnerability has been resolved:

bonding: 3ad: implement proper RCU rules for port->aggregator

syzbot found a data-race in bond3adgetactiveagginfo / bond3adstatemachine_handler [1] which hints at lack of proper RCU implementation.

Add __rcu qualifier to port->aggregator, and add proper RCU API.

[1]

BUG: KCSAN: data-race in bond3adgetactiveagginfo / bond3adstatemachine_handler

write to 0xffff88813cf5c4b0 of 8 bytes by task 36 on cpu 0: adportselectionlogic drivers/net/bonding/bond3ad.c:1659 [inline] bond3adstatemachinehandler+0x9d5/0x2d60 drivers/net/bonding/bond3ad.c:2569 processonework kernel/workqueue.c:3302 [inline] processscheduledworks+0x4f0/0x9c0 kernel/workqueue.c:3385 workerthread+0x58a/0x780 kernel/workqueue.c:3466 kthread+0x22a/0x280 kernel/kthread.c:436 retfromfork+0x146/0x330 arch/x86/kernel/process.c:158 retfromforkasm+0x1a/0x30 arch/x86/entry/entry64.S:245

read to 0xffff88813cf5c4b0 of 8 bytes by task 22063 on cpu 1: __bond3adgetactiveagginfo drivers/net/bonding/bond3ad.c:2858 [inline] bond3adgetactiveagginfo+0x8c/0x230 drivers/net/bonding/bond3ad.c:2881 bondfillinfo+0xe0f/0x10f0 drivers/net/bonding/bondnetlink.c:853 rtnllinkinfofill net/core/rtnetlink.c:906 [inline] rtnllinkfill+0x1d7/0x4e0 net/core/rtnetlink.c:927 rtnlfillifinfo+0xf8e/0x1380 net/core/rtnetlink.c:2168 rtmsgifinfobuildskb+0x11c/0x1b0 net/core/rtnetlink.c:4453 rtmsgifinfoevent net/core/rtnetlink.c:4486 [inline] rtmsgifinfo+0x6d/0x110 net/core/rtnetlink.c:4495 __devnotifyflags+0x76/0x390 net/core/dev.c:9790 netifchangeflags+0xac/0xd0 net/core/dev.c:9823 dosetlink+0x905/0x2950 net/core/rtnetlink.c:3180 rtnlgroup_changelink net/core/rtnetlink.c:3813 [inline] __rtnlnewlink net/core/rtnetlink.c:3981 [inline] rtnlnewlink+0xf55/0x1400 net/core/rtnetlink.c:4109 rtnetlinkrcvmsg+0x64b/0x720 net/core/rtnetlink.c:6995 netlinkrcvskb+0x123/0x220 net/netlink/afnetlink.c:2550 rtnetlinkrcv+0x1c/0x30 net/core/rtnetlink.c:7022 netlinkunicastkernel net/netlink/afnetlink.c:1318 [inline] netlinkunicast+0x5a8/0x680 net/netlink/afnetlink.c:1344 netlinksendmsg+0x5c8/0x6f0 net/netlink/afnetlink.c:1894 socksendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x563/0x5b0 net/socket.c:2698 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2752 __sys_sendmsg net/socket.c:2784 [inline] __dosyssendmsg net/socket.c:2789 [inline] __sesyssendmsg net/socket.c:2787 [inline] _x64syssendmsg+0xd4/0x160 net/socket.c:2787 x64syscall+0x194c/0x3020 arch/x86/include/generated/asm/syscalls64.h:47 dosyscallx64 arch/x86/entry/syscall64.c:63 [inline] dosyscall64+0x12c/0x3b0 arch/x86/entry/syscall64.c:94 entrySYSCALL64afterhwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff88813cf5c400

Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 22063 Comm: syz.0.31122 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026