From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,DKIM_VALID_EF,T_SPF_HELO_TEMPERROR,T_SPF_TEMPERROR, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by gnuweeb.org (Postfix) with ESMTPS id A0F907E2F8 for ; Sun, 27 Mar 2022 22:52:28 +0000 (UTC) Authentication-Results: gnuweeb.org; dkim=pass (1024-bit key; unprotected) header.d=alien8.de header.i=@alien8.de header.a=rsa-sha256 header.s=dkim header.b=GaWshRQG; dkim-atps=neutral Received: from zn.tnic (p2e55dff8.dip0.t-ipconnect.de [46.85.223.248]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 223E81EC01A2; Mon, 28 Mar 2022 00:52:23 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1648421543; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=fXK18M0KVpIRPx1rmbaiuZ7FWqGHqgKnqmOp0B4zeeI=; b=GaWshRQG9YEh7hi3v6G7o2WOoPQsxZ47PZDGD+OCVzj7XsICK71UpDRwiUZ6GlGNh9x1th vkcutIyO7RY1JTUqKsQDWOiYDWHNsNCX5mgU9DdhTVFzLR3I2/8SGXkrzQE9vGrBeFXCuL vwdSRMu4G1L85J4Av5rMwFN2f2n14hI= Date: Mon, 28 Mar 2022 00:52:19 +0200 From: Borislav Petkov To: Ammar Faizi Cc: Thomas Gleixner , Alviro Iskandar Setiawan , Alviro Iskandar Setiawan , Dave Hansen , Greg Kroah-Hartman , "H. Peter Anvin" , Ingo Molnar , Tony Luck , Yazen Ghannam , linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, gwml@vger.gnuweeb.org, x86@kernel.org Subject: Re: [PATCH v5 2/2] x86/MCE/AMD: Fix memory leak when `threshold_create_bank()` fails Message-ID: References: <20220310015306.445359-1-ammarfaizi2@gnuweeb.org> <20220310015306.445359-3-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220310015306.445359-3-ammarfaizi2@gnuweeb.org> List-Id: On Thu, Mar 10, 2022 at 08:53:06AM +0700, Ammar Faizi wrote: > In mce_threshold_create_device(), if threshold_create_bank() fails, the > @bp will be leaked, because the call to mce_threshold_remove_device() > will not free the @bp. mce_threshold_remove_device() frees > @threshold_banks. At that point, the @bp has not been written to > @threshold_banks, @threshold_banks is NULL, so the call is just a nop. > > Fix this by extracting the cleanup part into a new static function > _mce_threshold_remove_device(), then call it from create/remove device > functions. > > Also, eliminate the "goto out_err", just early return inside the loop > if the creation fails. > > Cc: Borislav Petkov > Cc: Thomas Gleixner > Cc: Greg Kroah-Hartman > Cc: stable@vger.kernel.org # v5.8+ > Fixes: 6458de97fc15 ("x86/mce/amd: Straighten CPU hotplug path") How did you decide this is the commit that this is fixing? > Link: https://lore.kernel.org/lkml/9dfe087a-f941-1bc4-657d-7e7c198888ff@gnuweeb.org That Link tag is not needed. > Co-authored-by: Alviro Iskandar Setiawan > Signed-off-by: Alviro Iskandar Setiawan > Co-authored-by: Yazen Ghannam There's no "Co-authored-by". The correct tag is described in Documentation/process/submitting-patches.rst Please make sure you've read that file before sending patches. > Signed-off-by: Yazen Ghannam > Signed-off-by: Ammar Faizi > --- > arch/x86/kernel/cpu/mce/amd.c | 32 +++++++++++++++++++------------- > 1 file changed, 19 insertions(+), 13 deletions(-) ... > @@ -1350,15 +1357,14 @@ int mce_threshold_create_device(unsigned int cpu) > if (!(this_cpu_read(bank_map) & (1 << bank))) > continue; > err = threshold_create_bank(bp, cpu, bank); > - if (err) > - goto out_err; > + if (err) { > + _mce_threshold_remove_device(bp, numbanks); > + return err; > + } > } > this_cpu_write(threshold_banks, bp); Do I see it correctly that the publishing of the @bp pointer - i.e., this line - should be moved right above the for loop? Then mce_threshold_remove_device() would properly free it in the error case and your patch turns into a oneliner? And then your Fixes: tag would be correct too... -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette