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 bond_3ad_get_active_agg_info /

bond_3ad_state_machine_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 bond_3ad_get_active_agg_info / bond_3ad_state_machine_handler

write to 0xffff88813cf5c4b0 of 8 bytes by task 36 on cpu 0:

ad_port_selection_logic drivers/net/bonding/bond_3ad.c:1659 [inline]

bond_3ad_state_machine_handler+0x9d5/0x2d60 drivers/net/bonding/bond_3ad.c:2569

process_one_work kernel/workqueue.c:3302 [inline]

process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385

worker_thread+0x58a/0x780 kernel/workqueue.c:3466

kthread+0x22a/0x280 kernel/kthread.c:436

ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158

ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88813cf5c4b0 of 8 bytes by task 22063 on cpu 1:

__bond_3ad_get_active_agg_info drivers/net/bonding/bond_3ad.c:2858 [inline]

bond_3ad_get_active_agg_info+0x8c/0x230 drivers/net/bonding/bond_3ad.c:2881

bond_fill_info+0xe0f/0x10f0 drivers/net/bonding/bond_netlink.c:853

rtnl_link_info_fill net/core/rtnetlink.c:906 [inline]

rtnl_link_fill+0x1d7/0x4e0 net/core/rtnetlink.c:927

rtnl_fill_ifinfo+0xf8e/0x1380 net/core/rtnetlink.c:2168

rtmsg_ifinfo_build_skb+0x11c/0x1b0 net/core/rtnetlink.c:4453

rtmsg_ifinfo_event net/core/rtnetlink.c:4486 [inline]

rtmsg_ifinfo+0x6d/0x110 net/core/rtnetlink.c:4495

__dev_notify_flags+0x76/0x390 net/core/dev.c:9790

netif_change_flags+0xac/0xd0 net/core/dev.c:9823

do_setlink+0x905/0x2950 net/core/rtnetlink.c:3180

rtnl_group_changelink net/core/rtnetlink.c:3813 [inline]

__rtnl_newlink net/core/rtnetlink.c:3981 [inline]

rtnl_newlink+0xf55/0x1400 net/core/rtnetlink.c:4109

rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:6995

netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550

rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7022

netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]

netlink_unicast+0x5a8/0x680 net/netlink/af_netlink.c:1344

netlink_sendmsg+0x5c8/0x6f0 net/netlink/af_netlink.c:1894

sock_sendmsg_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]

__do_sys_sendmsg net/socket.c:2789 [inline]

__se_sys_sendmsg net/socket.c:2787 [inline]

__x64_sys_sendmsg+0xd4/0x160 net/socket.c:2787

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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94

entry_SYSCALL_64_after_hwframe+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