CVE-2025-71091

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

team: fix check for port enabled in team_queue_override_port_prio_changed()

There has been a syzkaller bug reported recently with the following

trace:

list_del corruption, ffff888058bea080->prev is LIST_POISON2 (dead000000000122)

------------[ cut here ]------------

kernel BUG at lib/list_debug.c:59!

Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI

CPU: 3 UID: 0 PID: 21246 Comm: syz.0.2928 Not tainted syzkaller #0 PREEMPT(full)

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014

RIP: 0010:__list_del_entry_valid_or_report+0x13e/0x200 lib/list_debug.c:59

Code: 48 c7 c7 e0 71 f0 8b e8 30 08 ef fc 90 0f 0b 48 89 ef e8 a5 02 55 fd 48 89 ea 48 89 de 48 c7 c7 40 72 f0 8b e8 13 08 ef fc 90 <0f> 0b 48 89 ef e8 88 02 55 fd 48 89 ea 48 b8 00 00 00 00 00 fc ff

RSP: 0018:ffffc9000d49f370 EFLAGS: 00010286

RAX: 000000000000004e RBX: ffff888058bea080 RCX: ffffc9002817d000

RDX: 0000000000000000 RSI: ffffffff819becc6 RDI: 0000000000000005

RBP: dead000000000122 R08: 0000000000000005 R09: 0000000000000000

R10: 0000000080000000 R11: 0000000000000001 R12: ffff888039e9c230

R13: ffff888058bea088 R14: ffff888058bea080 R15: ffff888055461480

FS: 00007fbbcfe6f6c0(0000) GS:ffff8880d6d0a000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000110c3afcb0 CR3: 00000000382c7000 CR4: 0000000000352ef0

Call Trace:

<TASK>

__list_del_entry_valid include/linux/list.h:132 [inline]

__list_del_entry include/linux/list.h:223 [inline]

list_del_rcu include/linux/rculist.h:178 [inline]

__team_queue_override_port_del drivers/net/team/team_core.c:826 [inline]

__team_queue_override_port_del drivers/net/team/team_core.c:821 [inline]

team_queue_override_port_prio_changed drivers/net/team/team_core.c:883 [inline]

team_priority_option_set+0x171/0x2f0 drivers/net/team/team_core.c:1534

team_option_set drivers/net/team/team_core.c:376 [inline]

team_nl_options_set_doit+0x8ae/0xe60 drivers/net/team/team_core.c:2653

genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115

genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]

genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210

netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552

genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219

netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]

netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346

netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896

sock_sendmsg_nosec net/socket.c:727 [inline]

__sock_sendmsg net/socket.c:742 [inline]

____sys_sendmsg+0xa98/0xc70 net/socket.c:2630

___sys_sendmsg+0x134/0x1d0 net/socket.c:2684

__sys_sendmsg+0x16d/0x220 net/socket.c:2716

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]

do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94

entry_SYSCALL_64_after_hwframe+0x77/0x7f

The problem is in this flow:

1) Port is enabled, queue_id != 0, in qom_list

2) Port gets disabled

-> team_port_disable()

-> team_queue_override_port_del()

-> del (removed from list)

3) Port is disabled, queue_id != 0, not in any list

4) Priority changes

-> team_queue_override_port_prio_changed()

-> checks: port disabled && queue_id != 0

-> calls del - hits the BUG as it is removed already

To fix this, change the check in team_queue_override_port_prio_changed()

so it returns early if port is not enabled.