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Subject[PATCH 5.10 021/167] bonding: fix suspicious RCU usage in bond_ipsec_offload_ok()
Date
From: Taehee Yoo <ap420073@gmail.com>

[ Upstream commit 955b785ec6b3b2f9b91914d6eeac8ee66ee29239 ]

To dereference bond->curr_active_slave, it uses rcu_dereference().
But it and the caller doesn't acquire RCU so a warning occurs.
So add rcu_read_lock().

Splat looks like:
WARNING: suspicious RCU usage
5.13.0-rc6+ #1179 Not tainted
drivers/net/bonding/bond_main.c:571 suspicious
rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
1 lock held by ping/974:
#0: ffff888109e7db70 (sk_lock-AF_INET){+.+.}-{0:0},
at: raw_sendmsg+0x1303/0x2cb0

stack backtrace:
CPU: 2 PID: 974 Comm: ping Not tainted 5.13.0-rc6+ #1179
Call Trace:
dump_stack+0xa4/0xe5
bond_ipsec_offload_ok+0x1f4/0x260 [bonding]
xfrm_output+0x179/0x890
xfrm4_output+0xfa/0x410
? __xfrm4_output+0x4b0/0x4b0
? __ip_make_skb+0xecc/0x2030
? xfrm4_udp_encap_rcv+0x800/0x800
? ip_local_out+0x21/0x3a0
ip_send_skb+0x37/0xa0
raw_sendmsg+0x1bfd/0x2cb0

Fixes: 18cb261afd7b ("bonding: support hardware encryption offload to slaves")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/bonding/bond_main.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 484784757073..9aa2d79aa942 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -557,24 +557,34 @@ static bool bond_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
struct net_device *real_dev;
struct slave *curr_active;
struct bonding *bond;
+ int err;

bond = netdev_priv(bond_dev);
+ rcu_read_lock();
curr_active = rcu_dereference(bond->curr_active_slave);
real_dev = curr_active->dev;

- if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP)
- return true;
+ if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
+ err = true;
+ goto out;
+ }

- if (!xs->xso.real_dev)
- return false;
+ if (!xs->xso.real_dev) {
+ err = false;
+ goto out;
+ }

if (!real_dev->xfrmdev_ops ||
!real_dev->xfrmdev_ops->xdo_dev_offload_ok ||
netif_is_bond_master(real_dev)) {
- return false;
+ err = false;
+ goto out;
}

- return real_dev->xfrmdev_ops->xdo_dev_offload_ok(skb, xs);
+ err = real_dev->xfrmdev_ops->xdo_dev_offload_ok(skb, xs);
+out:
+ rcu_read_unlock();
+ return err;
}

static const struct xfrmdev_ops bond_xfrmdev_ops = {
--
2.30.2


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