From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4E641FA3741 for ; Fri, 2 Jan 2026 14:39:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A02AE6B0088; Fri, 2 Jan 2026 09:39:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9B1046B0089; Fri, 2 Jan 2026 09:39:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8BCCF6B008A; Fri, 2 Jan 2026 09:39:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 7B5806B0088 for ; Fri, 2 Jan 2026 09:39:56 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 3808D1A0390 for ; Fri, 2 Jan 2026 14:39:56 +0000 (UTC) X-FDA: 84287283192.24.0B9398B Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf13.hostedemail.com (Postfix) with ESMTP id B0B2820003 for ; Fri, 2 Jan 2026 14:39:54 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=RXgNzwE1; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf13.hostedemail.com: domain of sj@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1767364794; a=rsa-sha256; cv=none; b=GYSGpxBSaoHsYTjCYxJiigLgWtXR887XFfYewrAvAzw2wGHDdvsxN96ZRUksWh8ahS8pVd t6TEa97gcx2WqUlHNVEyI1uWFF0S0YD4AQrJRl4NEfU353UiJAzsqa+R7oqv2OGCy8fbcC 0fTVdDTFznErd27Y6mS/3yLvP814R3A= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=RXgNzwE1; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf13.hostedemail.com: domain of sj@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767364794; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=xZ7bttNFq8mEFSC+woqAoH+Q6JWLvlflVgFuk+TD6cI=; b=GEzoU6dULewvO36KFiTZvJWyYFOXxE6XAP+hmvXLyc9fPPQa/adZx/7gP74NlwaALNRrTM IZWbXR5MOawHYCXI5YULh0M76gMi7IaPgLIAUFauLb7Ol02wQ5n9adRpwAEV1SEWzIVX4d 3tSH4wj5Zwp/ttTrzbALfpWQiArlCXQ= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 19D9C60017; Fri, 2 Jan 2026 14:39:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 388D9C116B1; Fri, 2 Jan 2026 14:39:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767364793; bh=NFZVoW1OohheL/BZDD6iCVBR2TX6b8zaD6eMYXzwGC8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RXgNzwE1SI2gpupR21FN6yuKt9r1m+RG+oRnu4dmMGaqYzlROAwmSbKIxdJyAAY8y A2qostlhny+u7wwk9+qnCK+iHV6Rg8x6+vkCkqvPsZRE5WGcs7IvAuD5aNxb9+aKsU tja4L1XojxOxK6owOsA+H09OrqC91aszlbF2o8Zuog9sxHD4Ywd3pkvuMAwJQb3wKC nvKbyPM13uaCtR4yArs7ZCrEx1iCFkdIwrjaRPyordGYipEg/86e5AVKfFq5eRy5A0 FTCyCwWMNQUSUQCHwYB3pVrP/KA+5xQXztKFWvrX9wF9inBePMp1gFnnpCQM/1tvMn qrSiKGdQVvMlg== From: SeongJae Park To: Pavel Butsykin Cc: SeongJae Park , hannes@cmpxchg.org, yosry.ahmed@linux.dev, nphamcs@gmail.com, chengming.zhou@linux.dev, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mm/zswap: fix error pointer free in zswap_cpu_comp_prepare() Date: Fri, 2 Jan 2026 06:39:44 -0800 Message-ID: <20260102143945.52356-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: B0B2820003 X-Rspamd-Server: rspam03 X-Stat-Signature: 47a1uixcuq1q658utjsdsty1mdinag6h X-Rspam-User: X-HE-Tag: 1767364794-536232 X-HE-Meta: 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 wzI4yWLP EZOo0MzLqaLT3HTHuvQHdOBZi75DxGwPVkAu7Zm30+IUH1cg/FY83a0/ClFcbHiZ7e/4R8O8HhW9WZOCp/hGpDthcuRo0L2wsDModdQlBEyhxcBt864iRg6tZtKaVRXPjR21f7TTF9bENxgsZZi6s74F7nn6uhxHmNrGV4osMFHXToZ3uXOXylLichanueEUcfmz/WR7C9V8tlKHdL9vKhg3WePpgktWOBxbapg4/uoi5RBkxIBmYZqdjfBVO07/SWWQRxEFrovj4fo81d0kmMYtoaeuF5Qwkh/Xrr9yS5HQvd0X//zqS9WCESY8OsVZa3kIhtqfz0yDwhAQ2FVeOnyiVgg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 2 Jan 2026 10:51:01 +0400 Pavel Butsykin wrote: > On 1/1/26 04:32, SeongJae Park wrote: > > On Wed, 31 Dec 2025 11:46:38 +0400 Pavel Butsykin wrote: > > > >> crypto_alloc_acomp_node() may return ERR_PTR(), but the fail path checks > >> only for NULL and can pass an error pointer to crypto_free_acomp(). > >> Use IS_ERR_OR_NULL() to only free valid acomp instances. > >> > >> Fixes: 779b9955f643 ("mm: zswap: move allocations during CPU init outside the lock") > >> Cc: stable@vger.kernel.org > >> Signed-off-by: Pavel Butsykin > >> --- > >> mm/zswap.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/mm/zswap.c b/mm/zswap.c > >> index 5d0f8b13a958..ac9b7a60736b 100644 > >> --- a/mm/zswap.c > >> +++ b/mm/zswap.c > >> @@ -787,7 +787,7 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node) > >> return 0; > >> > >> fail: > >> - if (acomp) > >> + if (!IS_ERR_OR_NULL(acomp)) > >> crypto_free_acomp(acomp); > >> kfree(buffer); > >> return ret; > > > > I understand you are keeping NULL case to keep the old behavior. But, seems > > the case cannot happen to me for following reasons. > > > > First of all, the old NULL check was only for crypto_alloc_acomp_node() > > failure. But crypto_alloc_acomp_node() seems not returning NULL, to by breif > > look of the code. And the failure check of crypto_alloc_acomp_node() is > > actually doing only IS_ERR() check. > > > > So, it seems IS_ERR() here is enough. Or, if I missed a case that > > crypto_alloc_acomp_node() returns NULL, the above crypto_alloc_acomp_node() > > failure check should be updated to use IS_ERR_OR_NULL()? > > > > We have 'goto fail;' right before crypto_alloc_acomp_node() for the case > where kmalloc_node fails to allocate memory. In that case, 'acomp' will > still be initialized to NULL. Ah, you are right. Thank you for fixing this. Please feel free to add Reviewed-by: SeongJae Park Thanks, SJ [...]