From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8DE0F13AA3E; Sat, 14 Jun 2025 18:37:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749926235; cv=none; b=qS5r5PEgsNig0y1LvM/HegSkix7hLjQ0IZwgnAoFf2VpX/+Lc9hq0StVL5WtCaC3CGCT438t3SS8eQYB1Xi7tO5NEmhiM/neKCpAJImhHuhsRyW72gHWb4S5s0ULmRRSfmLVpu1H/pEvfYN5bJJ3ZMwF8BVE2fJVZZ+cejWxdMc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749926235; c=relaxed/simple; bh=G+P66hoOSUSIwWlKroYcgaEw3Vouu378clFj4f1qjW8=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=lZSMoAZ6p5BANlnc6GdOlvrUqP1VllDleyiHwcmqplcFkvTgOBjq47W/Vwy7tr8w1kWOSw0HyqX5CcFs26Uz8URa0nPwxBOj3bq8zABWKRl7XeZBT0F/trA8n4DaykeLEuW27tlS8Lt/koZNcBIu1jXqbvGvH/gt+bAb/JF++JU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=d63Zb6Jd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="d63Zb6Jd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B516AC4CEEB; Sat, 14 Jun 2025 18:37:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749926235; bh=G+P66hoOSUSIwWlKroYcgaEw3Vouu378clFj4f1qjW8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=d63Zb6JdkP/EPZFsk18bYDpcx3yR7oGSkzJ5wV2n5hr7vBl7bULiQFCojNen4GEqs qtT6/b0xfrqryPNaN+4sJoCsUM479aZrH8glgeeTXasWdYQVszFHIXv8xs+B/ePF31 dpy6NFRIxoYLoV/Q/imCrIJv1U7a+HZXN8sVp0vTKjf+t24XrquAcyxF9MzLg9dvjX 9JI+FbcTHD8f3hwKD6Ycpq5FsmPVB3pnDBDNewNraPav8/cPZkMs7PoNWTiLxyPmT2 LFYNsHWDJ7uzYY+B/kbIZfYlnSYerdQtWY5y8OOj20gRKbPKrobwEEpzmsu1MlDdI4 ZxhWdCnfxwXzg== Date: Sat, 14 Jun 2025 11:37:13 -0700 From: Jakub Kicinski To: Mina Almasry Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Andrew Lunn , Shuah Khan Subject: Re: [PATCH net-next v1 1/4] net: netmem: fix skb_ensure_writable with unreadable skbs Message-ID: <20250614113713.46b69771@kernel.org> In-Reply-To: <20250613042804.3259045-1-almasrymina@google.com> References: <20250613042804.3259045-1-almasrymina@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 13 Jun 2025 04:28:01 +0000 Mina Almasry wrote: > skb_ensure_writable actually makes sure that the header of the skb is > writable, and doesn't touch the payload. It doesn't need an > skb_frags_readable check. "doesn't touch the payload" is a bit misleading. What I'd say instead is that the pskb_may_pull() call about ensures that write_len is within the head, and will already fail if write_len would dip into unreadable frags. > Removing this check restores DSCP functionality with unreadable skbs as > it's called from dscp_tg. > > Fixes: 65249feb6b3d ("net: add support for skbs with unreadable frags") > > Signed-off-by: Mina Almasry Either no Fixes tag or send it to net. I think net is fine, this is clearly incorrect. By definition devmem should not prevent header modifications, so net? nit: no empty lines between tags -- pw-bot: cr