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Date:   Thu, 4 Aug 2022 18:03:46 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Abhishek Shah <abhishek.shah@columbia.edu>
Cc:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        netdev@vger.kernel.org, pabeni@redhat.com,
        steffen.klassert@secunet.com, linux-kernel@vger.kernel.org,
        Gabriel Ryan <gabe@cs.columbia.edu>,
        Fan Du <fan.du@windriver.com>,
        Steffen Klassert <klassert@kernel.org>
Subject: [PATCH] af_key: Do not call xfrm_probe_algs in parallel
Message-ID: <YuuZgsdmJK8roKLD@gondor.apana.org.au>
References: <CAEHB24-9hXY+TgQKxJB4bE9a9dFD9C+Lan+ShBwpvwaHVAGMFg@mail.gmail.com>
 <YtoWqEkKzvimzWS5@gondor.apana.org.au>
 <CAEHB249ygptvp9wpynMF7zZ2Kcet0+bwLVuVg5UReZHOU1+8HA@mail.gmail.com>
 <YuNGR/5U5pSo6YM3@gondor.apana.org.au>
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When namespace support was added to xfrm/afkey, it caused the
previously single-threaded call to xfrm_probe_algs to become
multi-threaded.  This is buggy and needs to be fixed with a mutex.

Reported-by: Abhishek Shah <abhishek.shah@columbia.edu>
Fixes: 283bc9f35bbb ("xfrm: Namespacify xfrm state/policy locks")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/net/key/af_key.c b/net/key/af_key.c
index fb16d7c4e1b8..20e73643b9c8 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1697,9 +1697,12 @@ static int pfkey_register(struct sock *sk, struct sk_buff *skb, const struct sad
 		pfk->registered |= (1<<hdr->sadb_msg_satype);
 	}
 
+	mutex_lock(&pfkey_mutex);
 	xfrm_probe_algs();
 
 	supp_skb = compose_sadb_supported(hdr, GFP_KERNEL | __GFP_ZERO);
+	mutex_unlock(&pfkey_mutex);
+
 	if (!supp_skb) {
 		if (hdr->sadb_msg_satype != SADB_SATYPE_UNSPEC)
 			pfk->registered &= ~(1<<hdr->sadb_msg_satype);
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt