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[79.184.131.109]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c25ab2f9aa6sm24499566b.35.2026.08.30.23.27.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Aug 2026 23:27:50 -0700 (PDT) From: Jakub Sitnicki Date: Mon, 31 Aug 2026 08:27:39 +0200 Subject: [PATCH net-next 2/2] net: Make skb_ext_put_mctp() idempotent Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260831-skb-ext-prep-work-v1-2-ecc2a8542fd9@cloudflare.com> References: <20260831-skb-ext-prep-work-v1-0-ecc2a8542fd9@cloudflare.com> In-Reply-To: <20260831-skb-ext-prep-work-v1-0-ecc2a8542fd9@cloudflare.com> To: netdev@vger.kernel.org, Florian Westphal , Paolo Abeni Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Simon Horman , Jeremy Kerr , Matt Johnston , Steffen Klassert , Herbert Xu , kernel-team@cloudflare.com X-Mailer: b4 0.16.0 The MCTP flow extension can be released either when it is deleted from an skb or when the last skb holding the extension block is freed. Handle the release in __skb_ext_del(), which is currently missing, and make skb_ext_put_mctp() safe to call from both paths. This will let __skb_ext_put() release the MCTP key without checking whether the extension is present first, which is needed if we want to reuse skb_ext chunks area after skb scrubbing. Suggested-by: Florian Westphal Signed-off-by: Jakub Sitnicki --- net/core/skbuff.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index aa8b42c74f42..ab195b99c853 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -7248,8 +7248,11 @@ static void skb_ext_put_sp(struct sec_path *sp) #ifdef CONFIG_MCTP_FLOWS static void skb_ext_put_mctp(struct mctp_flow *flow) { - if (flow->key) - mctp_key_unref(flow->key); + if (!flow->key) + return; + + mctp_key_unref(flow->key); + flow->key = NULL; } #endif @@ -7261,13 +7264,20 @@ void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id) if (skb->active_extensions == 0) { skb->extensions = NULL; __skb_ext_put(ext); -#ifdef CONFIG_XFRM - } else if (id == SKB_EXT_SEC_PATH && - refcount_read(&ext->refcnt) == 1) { + return; + } + + if (refcount_read(&ext->refcnt) > 1) + return; +#ifdef CONFIG_XFRM + if (id == SKB_EXT_SEC_PATH) skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH)); #endif - } +#ifdef CONFIG_MCTP_FLOWS + if (id == SKB_EXT_MCTP) + skb_ext_put_mctp(skb_ext_get_ptr(ext, SKB_EXT_MCTP)); +#endif } EXPORT_SYMBOL(__skb_ext_del); -- 2.43.0