6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jiawei Ye jiawei.ye@foxmail.com
[ Upstream commit fb86c42a2a5d44e849ddfbc98b8d2f4f40d36ee3 ]
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@foxmail.com Acked-by: Yonghong Song yonghong.song@linux.dev Link: https://lore.kernel.org/r/tencent_CFD3D1C3D68B45EA9F52D8EC76D2C4134306@qq.co... Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 a2467a7c01f9e..f9d05eff80b17 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2233,7 +2233,7 @@ 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: