From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 2D1D614533D for ; Thu, 16 May 2024 18:58:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=140.211.166.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715885938; cv=none; b=MlWVJ+GFx9LYGTj9DuMATGSBgyPPw9FfGyPK+HmEALpe3aKoWbXSgn5BYUjrhD/HxDXvAbO54NpPiSM+Gnj1FlYMWu/UuEhcCBRviENW0n2wg/Qnr0iQJJ8jxCnU6cdToG+pGfT39dtKoZHMyDqiQSuXYjFQuuu0r5KuV+bsy4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715885938; c=relaxed/simple; bh=mOGgssVkuZq/po829G7Wr9XNkIdjf3cEtZbegpQCjCI=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=Sr2Mo/wdT6HPpJaTc0vC79wMbYvtyT11Rg4CXDOZZGiUWhS/7E8vG/g6yTUsovH3Wg4pDNx9oPhAxlHdysjUJpN/Kar6dptaY56mry3wJDin/wm+raScFta5a0fgMR9joJk9i2LGRe/nZzhAca9oAA/dPnfNjTwKTMTc9L5D89Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sNDnHCQD; arc=none smtp.client-ip=140.211.166.133 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sNDnHCQD" Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id C8237403A2 for ; Thu, 16 May 2024 18:58:56 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org X-Spam-Flag: NO X-Spam-Score: -7.101 X-Spam-Level: Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id JErvlWIYHWCs for ; Thu, 16 May 2024 18:58:54 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=helgaas@kernel.org; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp2.osuosl.org B2EE6400A6 Authentication-Results: smtp2.osuosl.org; dmarc=pass (p=none dis=none) header.from=kernel.org DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org B2EE6400A6 Authentication-Results: smtp2.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=sNDnHCQD Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by smtp2.osuosl.org (Postfix) with ESMTPS id B2EE6400A6 for ; Thu, 16 May 2024 18:58:54 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 8DF2260AEE; Thu, 16 May 2024 18:58:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0771DC113CC; Thu, 16 May 2024 18:58:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715885933; bh=mOGgssVkuZq/po829G7Wr9XNkIdjf3cEtZbegpQCjCI=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=sNDnHCQDHtn6VUVbtC4knTUasTlSWgGTTXhz+vPAuhHnNHR2Twuu460lFMvKSLQ2z dizffqpdI12XJNR8VF8HA6+Q5M2WC9syCT8GBLomHredlphqXMk3+l3Hle13cY2BWX sUdX1DIckVf0+3g42d4ONynolQwqRwcsPCOBFBY+Zg56+6mMysdfT6BNpalGJUJDdC Ns4XWyAkc8yrFE7lbTZpkHsl3uKt9ytsCsKxG4RBbCVuA1g+JU9JicD2w5m9EL3WzQ sLt8vXZ2S9lPk0OIzr+9EI2SHrFP3O0WajerAN7Mt0GSpZkkOUsd0P/fFt5qTAuZ9F XvlPhWRrHVbqw== Date: Thu, 16 May 2024 13:58:51 -0500 From: Bjorn Helgaas To: yskelg@gmail.com Cc: Jaroslav Kysela , Takashi Iwai , skhan@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, Austin Kim , shjy180909@gmail.com, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] line6: add midibuf init failure handling in line6_init_midi() Message-ID: <20240516185851.GA2246377@bhelgaas> Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240516174737.415912-1-yskelg@gmail.com> On Fri, May 17, 2024 at 02:47:38AM +0900, yskelg@gmail.com wrote: > From: Yunseong Kim > > This patch fixes potential memory allocation failures in the > line6_midibuf_init(). If either midibuf_in, midibuf_out allocation > line6_midibuf_init call failed, the allocated memory for line6midi > might have been leaked. > > This patch introduces an error handling label and uses goto to jump there > in case of allocation failures. A kfree call is added to release any > partially allocated memory before returning the error code. > > Signed-off-by: Yunseong Kim Hi Yunseong, I don't maintain this area, but since you asked for feedback on IRC: For the subject line, run "git log --oneline sound/usb/line6/midi.c" and match the style, i.e., in this case it should be: ALSA: line6: ... "Add init failure handling" is not very specific; I think it's worth including the key word "leak" in the subject line. Remove text like "this patch". We already know which patch the commit log refers to. Use imperative mood in the commit log, not "introduces", "uses", "is added", etc. Details: https://chris.beams.io/posts/git-commit/ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=v6.9#n94 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/maintainer-tip.rst?id=v6.9#n134 The second paragraph ("... introduces an error handling label ...") basically translates the patch from C to English. No need for that since we can read the C. The commit log can be higher level to explain why the patch should be merged. In this case, the error paths leak the snd_line6_midi allocation (not "might"; it's definitely a leak). This case is so simple that you don't need much of a commit log. Adding too much detail almost obscures the point. Something like this would probably be sufficient: Free line6midi in error paths to avoid leaking the allocation. Nice work, good luck! Bjorn > --- > sound/usb/line6/midi.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/sound/usb/line6/midi.c b/sound/usb/line6/midi.c > index 0838632c788e..abcf58f46673 100644 > --- a/sound/usb/line6/midi.c > +++ b/sound/usb/line6/midi.c > @@ -283,13 +283,18 @@ int line6_init_midi(struct usb_line6 *line6) > > err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0); > if (err < 0) > - return err; > + goto error; > > err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1); > if (err < 0) > - return err; > + goto error; > > line6->line6midi = line6midi; > return 0; > + > +error: > + kfree(line6midi); > + return err; > + > } > EXPORT_SYMBOL_GPL(line6_init_midi); > -- > 2.34.1 >