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Thu, 21 May 2026 09:33:28 -0700 (PDT) Received: from fx.tailc0aff1.ts.net ([206.206.192.132]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13652ac2f39sm502917c88.15.2026.05.21.09.33.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 May 2026 09:33:28 -0700 (PDT) From: Weiming Shi To: netdev@vger.kernel.org Cc: willemdebruijn.kernel@gmail.com, jasowang@redhat.com, pabeni@redhat.com, kuba@kernel.org, edumazet@google.com, dongli.zhang@oracle.com, xmei5@asu.edu, linux-kernel@vger.kernel.org, Weiming Shi Subject: [PATCH net] tun: free page on build_skb failure in tun_xdp_one() Date: Thu, 21 May 2026 09:33:13 -0700 Message-ID: <20260521163312.1479805-2-bestswngs@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When build_skb() fails in tun_xdp_one(), the function sets ret to -ENOMEM and jumps to the out label, which returns without freeing the page that vhost_net_build_xdp() allocated for the frame. As with the short-frame rejection path, tun_sendmsg() discards the per-buffer error and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page. Each build_skb() failure in a batch leaks one page-frag chunk. Free the page before taking the error path, matching the put_page() the other error exits of tun_xdp_one() already perform. Fixes: 043d222f93ab ("tuntap: accept an array of XDP buffs through sendmsg(= )") Reported-by: Xiang Mei Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Weiming Shi Reviewed-by: Dongli Zhang Reviewed-by: Willem de Bruijn --- drivers/net/tun.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index b183189f1853..39e9f3390c91 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2437,6 +2437,7 @@ static int tun_xdp_one(struct tun_struct *tun, build: skb =3D build_skb(xdp->data_hard_start, buflen); if (!skb) { + put_page(virt_to_head_page(xdp->data)); ret =3D -ENOMEM; goto out; } --=20 2.43.0