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 X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8E0EC4320A for ; Tue, 3 Aug 2021 14:29:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8CEA60F9C for ; Tue, 3 Aug 2021 14:29:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236488AbhHCO3a (ORCPT ); Tue, 3 Aug 2021 10:29:30 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:51552 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234328AbhHCO32 (ORCPT ); Tue, 3 Aug 2021 10:29:28 -0400 Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id DB6D0200DC; Tue, 3 Aug 2021 14:29:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1628000956; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gWrKPIOGbRT7mtmhi4hDLoxX8C67Y8PDNpZrScUS6w0=; b=Tim2TPOv9wguBc5UYs/2q3aNxdtCzt3xuEhZQ6YJaKgjtnLcefyBt/RgF/gyMr3w1YuRsC Nh6n9M/XEyY1H+pcDuDGEbY6XkcNuJLCKRCljqmtaFJl/Uz/R/p/MjjhzrZ7QJOZf5BbAV vnRKrRUB7BylmN7fC25l9lZyCplRvsY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1628000956; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gWrKPIOGbRT7mtmhi4hDLoxX8C67Y8PDNpZrScUS6w0=; b=96Vlx9kN67HaimN52bjyERk0X9UiBMS14sRHqKusL1x1PsoD7dH0on9OhBozpHt+8E7vvO uPSy2/IplePRpfCA== Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id B3C2813B74; Tue, 3 Aug 2021 14:29:16 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id 1oBCK7xSCWElZwAAGKfGzw (envelope-from ); Tue, 03 Aug 2021 14:29:16 +0000 Subject: Re: [PATCH] slub: fix unreclaimable slab stat for bulk free To: Kefeng Wang , Shakeel Butt Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Michal Hocko , Roman Gushchin , Wang Hai , Muchun Song , Andrew Morton , Linux MM , LKML References: <20210728155354.3440560-1-shakeelb@google.com> <8c14efe2-69dc-6eab-3cd5-c042576770e7@huawei.com> <35a0b75a-f348-d21c-4ff4-fadba0c4db02@huawei.com> From: Vlastimil Babka Message-ID: <43cf4e71-4dd4-dc37-a70f-553fe5cba126@suse.cz> Date: Tue, 3 Aug 2021 16:29:16 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <35a0b75a-f348-d21c-4ff4-fadba0c4db02@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/3/21 4:24 PM, Kefeng Wang wrote: > > On 2021/7/29 22:03, Shakeel Butt wrote: >> On Wed, Jul 28, 2021 at 11:52 PM Kefeng Wang wrote: >>> >>> On 2021/7/28 23:53, Shakeel Butt wrote: >> I don't have a strong opinion on this. Please send a patch with >> reasoning if you want WARN_ON_ONCE here. > > Ok, we met a BUG_ON(!PageCompound(page)) in kfree() twice in lts4.4, we are > still debugging it. > > It's different to analyses due to no vmcore, and can't be reproduced. > > WARN_ON() here could help us to notice the issue. > > Also is there any experience or known fix/way to debug this kinds of issue? > memory corruption? This would typically be a use-after-free/double-free - a problem of the slab user, not slab itself. > Any suggestion will be appreciated, thanks. debug_pagealloc could help to catch a use-after-free earlier > >> . >>