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 0CB0EC27C76 for ; Wed, 25 Jan 2023 14:47:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 65A606B0073; Wed, 25 Jan 2023 09:47:32 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 609C26B0075; Wed, 25 Jan 2023 09:47:32 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4F8D66B0078; Wed, 25 Jan 2023 09:47:32 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 3E0AE6B0073 for ; Wed, 25 Jan 2023 09:47:32 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 19CB6407DA for ; Wed, 25 Jan 2023 14:47:32 +0000 (UTC) X-FDA: 80393599944.06.19EC6E4 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf14.hostedemail.com (Postfix) with ESMTP id 474BD100014 for ; Wed, 25 Jan 2023 14:47:30 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf14.hostedemail.com: domain of cmarinas@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1674658050; 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; bh=r0Myj+S4tNhOb97Ztm8FGZyJWJh7pBQbBgRo1/5e/n4=; b=OV8fO6gPI5ZD5t0s34N84Z0iYPqTmD3p3DvsQYBzvFJB/zNGGzQsGZ1ffsy3VsqqWmSsbI p7sjv5bsPyt+zqRTDX/jdBgjz2m5QqFwzf5fKvuyGk7TOCqUKSlovh3XDTKzU32fi0zZqb 2pU3H6shoy/kVnnjM/91lFU8iK+40MA= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf14.hostedemail.com: domain of cmarinas@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1674658050; a=rsa-sha256; cv=none; b=OkuaAcdvH8+eCSTqwL7ILZEDrAOHvjx5J0Ea1UjvYuXdNgTMtSYU2lRVB37ELWXoVeappF 9ybNVOAKF9zw1Z+zeaWmxdrxZLaFjmJiUh4IKvBbmA5oLRWlsH+1ImclTT/o/Ujb8tIqje ykXLdRtR7SMStqQf/nrJNoyDSdJYsHE= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 9891CB81A4A; Wed, 25 Jan 2023 14:47:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08D65C433D2; Wed, 25 Jan 2023 14:47:23 +0000 (UTC) Date: Wed, 25 Jan 2023 14:47:21 +0000 From: Catalin Marinas To: George Prekas Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Thomas Gleixner , "Eric W. Biederman" , Sebastian Andrzej Siewior , Andy Lutomirski , Peter Zijlstra , "Liam R. Howlett" , Fenghua Yu , Andrei Vagin Subject: Re: [PATCH 1/9] mm: kmemleak: properly disable task stack scanning Message-ID: References: <20230123170419.7292-1-george@enfabrica.net> <20230123170419.7292-2-george@enfabrica.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230123170419.7292-2-george@enfabrica.net> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 474BD100014 X-Stat-Signature: gitypxgp7fu31dycxia77m4y8rgo6k8x X-HE-Tag: 1674658050-838649 X-HE-Meta: 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 3sih9EjP 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 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: On Mon, Jan 23, 2023 at 11:04:11AM -0600, George Prekas wrote: > @@ -1586,23 +1608,6 @@ static void kmemleak_scan(void) > } > put_online_mems(); > > - /* > - * Scanning the task stacks (may introduce false negatives). > - */ > - if (kmemleak_stack_scan) { > - struct task_struct *p, *g; > - > - rcu_read_lock(); > - for_each_process_thread(g, p) { > - void *stack = try_get_task_stack(p); > - if (stack) { > - scan_block(stack, stack + THREAD_SIZE, NULL); > - put_task_stack(p); > - } > - } > - rcu_read_unlock(); > - } On architectures without VMAP_STACK, we still need the above otherwise it could lead to some false positives. -- Catalin