In the bpf_out_neigh_v6 function, rcu_read_lock() is used to begin an RCU
read-side critical section. However, when unlocking, one branch
incorrectly uses a different RCU unlock flavour rcu_read_unlock_bh()
instead of rcu_read_unlock(). This mismatch in RCU locking flavours can
lead to unexpected behavior and potential concurrency issues.
This possible bug was identified using a static analysis tool developed
by myself, specifically designed to detect RCU-related issues.
This patch corrects the mismatched unlock flavour by replacing the
incorrect rcu_read_unlock_bh() with the appropriate rcu_read_unlock(),
ensuring that the RCU critical section is properly exited. This change
prevents potential synchronization issues and aligns with proper RCU
usage patterns.
Fixes: 09eed1192cec ("neighbour: switch to standard rcu, instead of rcu_bh")
Signed-off-by: Jiawei Ye <jiawei.ye@xxxxxxxxxxx>
---
net/core/filter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 64248d0ac4ad..44bbc1dbfb50 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2232,7 +2232,7 @@ static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb,
rcu_read_unlock();
return ret;
}
- rcu_read_unlock_bh();
+ rcu_read_unlock();
if (dst)
IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
out_drop:
--
2.34.1
