From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4510382866 for ; Fri, 22 May 2026 23:07:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779491224; cv=none; b=Hy7qCSTNNOsI/Uq6Kynt+UzzsNHhfiSrxZye/FSQpUuA/q9bAT/DWPQE0oBjNN/2MNUvYg5JRyEROJtZ9W6bDTUEWrYmA8tFnkWwZdRNML7hkYRsE1I9uHQk+omrGTcnO3DCv/Mjn7+96me4yS0Ru50T9LPbOVi/m7UY+4Qd2rk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779491224; c=relaxed/simple; bh=bByBtITJ0CvKFHBvxRWfZQ2V9xHUTysGdPyT6ZLjZog=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZYsislBjdENmwWY188qNvef9qvAF6TlGcse7IL2SzpdM/RNRcD5wMTaYgffFmEZ4z1GqMn+Pa3SemldYbPH9laS62OHttQVC1Yj4W/aoiO4mSsfzF4wT8+SMC81sQeZDatHV+yWlNMCEKn03mtNnLwOJU5iaxMXzWpr978bNak0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VU2Xidto; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VU2Xidto" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB8E51F00A3D; Fri, 22 May 2026 23:07:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779491223; bh=ocU0C81LVhiuatd6m0R41vAaq7UqdSt2bU19xf+K+rY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=VU2XidtonAejoxF6+rdNy1yauLohQRSfeGqyVRoN0NSzUV4nj3nvTY/EFYDrb6+i4 AX1uVTuWUlrxS2DkjDN8QfACHs6zIm1L3su3eVY0BVt0NfpJU+/Shj525QnY/z1Z1b szIB2LNOMhcRpzv/XzVaCkGwSj8IyJC9W9/ns79jQFNu24iEG5nxaNj05hx6OBsN/v 6hpF9mHqiOrqOznqYCn1+MadAtK2FN6x2BYALf2iW2QAENJJjA0L73MO5QcyWndYFK 3Xg+uqANdn9ZP77nD/YkENwWe6CZn06lSPk7axjKTpvzJ/aa9c//sa0bJEQzuJgs26 q9a+P78rEwy5g== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, gal@nvidia.com, Jakub Kicinski , andrew@lunn.ch Subject: [PATCH net 1/6] ethtool: rss: avoid modifying the RSS context response Date: Fri, 22 May 2026 16:06:42 -0700 Message-ID: <20260522230647.1705600-2-kuba@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260522230647.1705600-1-kuba@kernel.org> References: <20260522230647.1705600-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Gemini says that we're modifying the RSS_CREATE response skb. I think it's right, the comment says that unicast() should unshare the skb but I'm not entirely sure what I meant there. netlink_trim() does a copy but only if skb is not well sized (it's at least 2x larger than necessary for the payload). Fixes: a166ab7816c5 ("ethtool: rss: support creating contexts via Netlink") Signed-off-by: Jakub Kicinski --- CC: andrew@lunn.ch CC: gal@nvidia.com --- net/ethtool/rss.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/net/ethtool/rss.c b/net/ethtool/rss.c index 353110b862ab..8ffec9785efa 100644 --- a/net/ethtool/rss.c +++ b/net/ethtool/rss.c @@ -981,11 +981,17 @@ ethnl_rss_create_validate(struct net_device *dev, struct genl_info *info) } static void -ethnl_rss_create_send_ntf(struct sk_buff *rsp, struct net_device *dev) +ethnl_rss_create_send_ntf(const struct sk_buff *rsp, struct net_device *dev) { - struct nlmsghdr *nlh = (void *)rsp->data; struct genlmsghdr *genl_hdr; + struct nlmsghdr *nlh; + struct sk_buff *ntf; + ntf = skb_copy_expand(rsp, 0, 0, GFP_KERNEL); + if (!ntf) + return; + + nlh = nlmsg_hdr(ntf); /* Convert the reply into a notification */ nlh->nlmsg_pid = 0; nlh->nlmsg_seq = ethnl_bcast_seq_next(); @@ -993,7 +999,7 @@ ethnl_rss_create_send_ntf(struct sk_buff *rsp, struct net_device *dev) genl_hdr = nlmsg_data(nlh); genl_hdr->cmd = ETHTOOL_MSG_RSS_CREATE_NTF; - ethnl_multicast(rsp, dev); + ethnl_multicast(ntf, dev); } int ethnl_rss_create_doit(struct sk_buff *skb, struct genl_info *info) @@ -1104,12 +1110,8 @@ int ethnl_rss_create_doit(struct sk_buff *skb, struct genl_info *info) genlmsg_end(rsp, hdr); - /* Use the same skb for the response and the notification, - * genlmsg_reply() will copy the skb if it has elevated user count. - */ - skb_get(rsp); - ret = genlmsg_reply(rsp, info); ethnl_rss_create_send_ntf(rsp, dev); + ret = genlmsg_reply(rsp, info); rsp = NULL; exit_unlock: -- 2.54.0