Medium · published January 31, 2025
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Fix inversion dependency warning while enabling IPsec tunnel
Attempt to enable IPsec packet offload in tunnel mode in debug kernel
generates the following kernel panic, which is happening due to two
issues:
1. In SA add section, the should be _bh() variant when marking SA mode.
2. There is not needed flush_workqueue in SA delete routine. It is not
needed as at this stage as it is removed from SADB and the running work
will be canceled later in SA free.
=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
6.12.0+ #4 Not tainted
-----------------------------------------------------
charon/1337 [HC0[0]:SC0[4]:HE1:SE0] is trying to acquire:
ffff88810f365020 (&xa->xa_lock#24){+.+.}-{3:3}, at: mlx5e_xfrm_del_state+0xca/0x1e0 [mlx5_core]
and this task is already holding:
ffff88813e0f0d48 (&x->lock){+.-.}-{3:3}, at: xfrm_state_delete+0x16/0x30
which would create a new lock dependency:
(&x->lock){+.-.}-{3:3} -> (&xa->xa_lock#24){+.+.}-{3:3}
but this new dependency connects a SOFTIRQ-irq-safe lock:
(&x->lock){+.-.}-{3:3}
... which became SOFTIRQ-irq-safe at:
lock_acquire+0x1be/0x520
_raw_spin_lock_bh+0x34/0x40
xfrm_timer_handler+0x91/0xd70
__hrtimer_run_queues+0x1dd/0xa60
hrtimer_run_softirq+0x146/0x2e0
handle_softirqs+0x266/0x860
irq_exit_rcu+0x115/0x1a0
sysvec_apic_timer_interrupt+0x6e/0x90
asm_sysvec_apic_timer_interrupt+0x16/0x20
default_idle+0x13/0x20
default_idle_call+0x67/0xa0
do_idle+0x2da/0x320
cpu_startup_entry+0x50/0x60
start_secondary+0x213/0x2a0
common_startup_64+0x129/0x138
to a SOFTIRQ-irq-unsafe lock:
(&xa->xa_lock#24){+.+.}-{3:3}
... which became SOFTIRQ-irq-unsafe at:
...
lock_acquire+0x1be/0x520
_raw_spin_lock+0x2c/0x40
xa_set_mark+0x70/0x110
mlx5e_xfrm_add_state+0xe48/0x2290 [mlx5_core]
xfrm_dev_state_add+0x3bb/0xd70
xfrm_add_sa+0x2451/0x4a90
xfrm_user_rcv_msg+0x493/0x880
netlink_rcv_skb+0x12e/0x380
xfrm_netlink_rcv+0x6d/0x90
netlink_unicast+0x42f/0x740
netlink_sendmsg+0x745/0xbe0
__sock_sendmsg+0xc5/0x190
__sys_sendto+0x1fe/0x2c0
__x64_sys_sendto+0xdc/0x1b0
do_syscall_64+0x6d/0x140
entry_SYSCALL_64_after_hwframe+0x4b/0x53
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&xa->xa_lock#24);
local_irq_disable();
lock(&x->lock);
lock(&xa->xa_lock#24);
<Interrupt>
lock(&x->lock);
*** DEADLOCK ***
2 locks held by charon/1337:
#0: ffffffff87f8f858 (&net->xfrm.xfrm_cfg_mutex){+.+.}-{4:4}, at: xfrm_netlink_rcv+0x5e/0x90
#1: ffff88813e0f0d48 (&x->lock){+.-.}-{3:3}, at: xfrm_state_delete+0x16/0x30
the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
-> (&x->lock){+.-.}-{3:3} ops: 29 {
HARDIRQ-ON-W at:
lock_acquire+0x1be/0x520
_raw_spin_lock_bh+0x34/0x40
xfrm_alloc_spi+0xc0/0xe60
xfrm_alloc_userspi+0x5f6/0xbc0
xfrm_user_rcv_msg+0x493/0x880
netlink_rcv_skb+0x12e/0x380
xfrm_netlink_rcv+0x6d/0x90
netlink_unicast+0x42f/0x740
netlink_sendmsg+0x745/0xbe0
__sock_sendmsg+0xc5/0x190
__sys_sendto+0x1fe/0x2c0
__x64_sys_sendto+0xdc/0x1b0
do_syscall_64+0x6d/0x140
entry_SYSCALL_64_after_hwframe+0x4b/0x53
IN-SOFTIRQ-W at:
lock_acquire+0x1be/0x520
_raw_spin_lock_bh+0x34/0x40
xfrm_timer_handler+0x91/0xd70
__hrtimer_run_queues+0x1dd/0xa60
---truncated---