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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AFEFC001E0 for ; Mon, 23 Oct 2023 04:57:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5598F6B00A3; Mon, 23 Oct 2023 00:57:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 50A456B00A4; Mon, 23 Oct 2023 00:57:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3F85B6B00A5; Mon, 23 Oct 2023 00:57:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 3123D6B00A3 for ; Mon, 23 Oct 2023 00:57:48 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E73D81608FE for ; Mon, 23 Oct 2023 04:57:47 +0000 (UTC) X-FDA: 81375518574.18.341B918 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) by imf14.hostedemail.com (Postfix) with ESMTP id E734310002D for ; Mon, 23 Oct 2023 04:57:45 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b=p0JUFnPp; spf=pass (imf14.hostedemail.com: domain of dan.carpenter@linaro.org designates 209.85.128.45 as permitted sender) smtp.mailfrom=dan.carpenter@linaro.org; dmarc=pass (policy=none) header.from=linaro.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1698037066; a=rsa-sha256; cv=none; b=sP2b9Le9UZoSRGlU487hLSPZbjmKBRarwFFQPLkFWWo0LCN55CMpk+EbaRrDhLiC5AJJUo tfu75EoqGz3htCBofn4p0vCRsVwU6N6DfcLaMZXC73bCp8hYPOwAkFu8fzf9MS0kvtWuJV 6780D+CFVbc6gWwBqd2w16lR1v9ZS8o= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b=p0JUFnPp; spf=pass (imf14.hostedemail.com: domain of dan.carpenter@linaro.org designates 209.85.128.45 as permitted sender) smtp.mailfrom=dan.carpenter@linaro.org; dmarc=pass (policy=none) header.from=linaro.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1698037066; 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-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=GGtz+/MQRxfrHAnpLCrq4BoXI5MCTMZCHiUBxRPLmA4=; b=RM3SGqCKT+7yCCbdVOLvcz1SLQhfvbXiQv6quS9KNEZiF8vVsXnMUUYTHH9zPCd2a+fdnE HJyCx92qiMjv0snEZuP8hj58nKfWTeOe7Cp3hmyB2aN/xDK31dpnD/VklladMc0UFUa9pL NlBEVB82vJiuL3yHymqL5lm0VEtP3oM= Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-4083cd39188so22144485e9.2 for ; Sun, 22 Oct 2023 21:57:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1698037064; x=1698641864; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=GGtz+/MQRxfrHAnpLCrq4BoXI5MCTMZCHiUBxRPLmA4=; b=p0JUFnPp3rYn2JDCmdRPSuytm9fSij+TPmFREZ/7VZ3F1ijrdQSuf8fc2nk9KU1kbr RdP/vKuGHr767GGIYI838XPJP79CX1f/aanw3W2FhzTWJrkh2ZcuXdE4eq3QiahY6fSv SQooYHCq/2WY8O7SK9iSqsO0ejuxdE66Z4CirkwziPpAu3hYefnTa9Z+HmsWIcjDul0h ZTPiXd96SZWfruT1A+kPuaJ03i2o4BTRPBfa5qWqfJgSWbvipI7fHAhYlM7lwweZpsqs WERsSCQwJwREN00i7b4O3TCtilpdCEkg/+lTJGNq04I0w7oMBhSHhq/gP/BQivUxUg3C zcyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698037064; x=1698641864; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=GGtz+/MQRxfrHAnpLCrq4BoXI5MCTMZCHiUBxRPLmA4=; b=lbZmdwdnRPyl0FmOCeUWNAUnnzVeEk/lTjlMb2PLuSKLeqUA3IeFWjoImrIXxdbbTp OgsW/+OVevgC8c4m3EKLtF3aO+UUxU6q2nEwjR6caeaGM0JmlKULB2ZmorY3o0/P1oyH Yhi8UZjIxgrF+OAvH441Lt1UDet6sH7itU81m1V8rmnLAaZvOYjYkzDKSW2FxbJiYLdH /L2T4NJ8LK9rxzX9V6hm+up4lvN7acibTQKIMY68s+U5QPVZRZTlbDmoSu3b50DNKt+u tU5t0ecNtad2s56/8GpRSss7qXcKUSNMUAMSQ5QwlCn3ybEsJoGonfjrc38/GyoqzeER xGUw== X-Gm-Message-State: AOJu0Yx2sSKj1eEQ9Db0iscQMZf+w2XlN4wcZTr5ZYHwGX1Z5ZHwNzcF BEeqdugBSkRv2Uwn62Oy1ewyuw== X-Google-Smtp-Source: AGHT+IHqIdzJg+L6hUh5BLy9YGIX2wSFREX8EVuNJRZShwD3/E5x+3628NUW3Ueua6+MNnid9Tvi7Q== X-Received: by 2002:a1c:7c0d:0:b0:406:53aa:7a5f with SMTP id x13-20020a1c7c0d000000b0040653aa7a5fmr6526369wmc.10.1698037064341; Sun, 22 Oct 2023 21:57:44 -0700 (PDT) Received: from localhost ([102.36.222.112]) by smtp.gmail.com with ESMTPSA id je20-20020a05600c1f9400b004063ea92492sm8536386wmb.22.2023.10.22.21.57.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Oct 2023 21:57:43 -0700 (PDT) Date: Mon, 23 Oct 2023 07:57:40 +0300 From: Dan Carpenter To: Andrew Morton Cc: Zach O'Keefe , Yang Shi , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH 1/2] mm/khugepaged: Fix an uninitialized variable bug Message-ID: References: <20231020093407.02be8ef4984ce31a7222f69f@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231020093407.02be8ef4984ce31a7222f69f@linux-foundation.org> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: E734310002D X-Stat-Signature: 5n9m36nm1teamtk53ebfdgeg18zkmxfr X-Rspam-User: X-HE-Tag: 1698037065-982090 X-HE-Meta: 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 a7XndrMg pORBf1w2KgKcDXd1gDezpmLtOY8v0ilmS4K/bsDqmlrzKkA53BFGuJcm1m7eYPxu5QvqVR5yOO7a4sAiE0A8NUOH9/Q2ud0lxEVzYAEDWJWO23B+7rDZWQKSEsbsRYc1tdNrvTDMzBruhDCc+DBK+kxmjlevVwaDmKZ5I5uYyLiimeCeHqie+kJuCo+5/vwGvDEnx8VNZfm79AVbqBnBjS0MX2FmwmYyR2JBOBEl9zLTSmH4p3ZntRzN2O9zPIZ0SqNTmlFZA0iqSojQwFPO6VC3R9oro9c2af+iU+iYK9MA9RPhUwc1KA5i8Dpwds0n3V4a7fYWNyRD5ifKl7FAyMpmSOqPyuoocXMrVTENtwfwUjRDqRyJDVYYxb8Bi3cjHoY3i3ndcIPz/RkKvq3SmBmbW44AZWdtGiJQrLrDl7dvEENIUP6i8ceDfBnTiujT5FJAk 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, Oct 20, 2023 at 09:34:07AM -0700, Andrew Morton wrote: > On Fri, 20 Oct 2023 17:13:32 +0300 Dan Carpenter wrote: > > > Smatch complains that "hpage" can be used uninitialized: > > > > mm/khugepaged.c:1234 collapse_huge_page() > > error: uninitialized symbol 'hpage'. > > > > Initialized it on this path. > > > > --- a/mm/khugepaged.c > > +++ b/mm/khugepaged.c > > @@ -1062,8 +1062,10 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, > > int node = hpage_collapse_find_target_node(cc); > > struct folio *folio; > > > > - if (!hpage_collapse_alloc_folio(&folio, gfp, node, &cc->alloc_nmask)) > > + if (!hpage_collapse_alloc_folio(&folio, gfp, node, &cc->alloc_nmask)) { > > + *hpage = NULL; > > return SCAN_ALLOC_HUGE_PAGE_FAIL; > > + } > > > > if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { > > folio_put(folio); > > Thanks. Seems this was accidentally fixed by > > Author: Peter Xu > AuthorDate: Wed Feb 22 14:52:47 2023 -0500 > Commit: Andrew Morton > CommitDate: Tue Mar 28 16:20:06 2023 -0700 > > mm/khugepaged: alloc_charge_hpage() take care of mem charge errors > > > Which was quite a long time ago. Are you scanning old kernel versions? There are two error paths. Peter's patch changed the second SCAN_CGROUP_CHARGE_FAIL error path but left the first SCAN_ALLOC_HUGE_PAGE_FAIL error path. To be honest, it's probably a better idea to just add a *hpage = NULL at the start of the function. regards, dan carpenter