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=-11.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 51E77C43461 for ; Fri, 11 Sep 2020 22:40:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B651D20770 for ; Fri, 11 Sep 2020 22:40:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="wWvQJhNN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B651D20770 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 049626B0003; Fri, 11 Sep 2020 18:40:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F3CF56B0037; Fri, 11 Sep 2020 18:40:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E51576B0055; Fri, 11 Sep 2020 18:40:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0151.hostedemail.com [216.40.44.151]) by kanga.kvack.org (Postfix) with ESMTP id CD0BA6B0003 for ; Fri, 11 Sep 2020 18:40:34 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 934BF1DF4 for ; Fri, 11 Sep 2020 22:40:34 +0000 (UTC) X-FDA: 77252251188.23.loss87_370d433270f2 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 6BBA637608 for ; Fri, 11 Sep 2020 22:40:34 +0000 (UTC) X-HE-Tag: loss87_370d433270f2 X-Filterd-Recvd-Size: 3814 Received: from mail-lj1-f194.google.com (mail-lj1-f194.google.com [209.85.208.194]) by imf12.hostedemail.com (Postfix) with ESMTP for ; Fri, 11 Sep 2020 22:40:33 +0000 (UTC) Received: by mail-lj1-f194.google.com with SMTP id a15so13798258ljk.2 for ; Fri, 11 Sep 2020 15:40:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QVD1gZDtb4fovFqzFSv9irG+x3sWgcFoSpx/oNvkoLE=; b=wWvQJhNNIRUX720qs0qN6+3c+1AchsI6qKG/w09Wn7lBRPPTO9VrrYHzLzstivrpb+ 1ntUr9NR+s11KMAsEoV2yW5FVFhWj/UMQzNeUlnXk9b4of6XLFIL95AQZBMFzXDsgEzo 8ufltuCI0KxK+2XTSpc08ZmJ4BoPeH2CA89Y0qQTRX78I9bJtA9NGelq3Hi04uPzbl10 S64Oow+7ks4NSY/8yQlfgPXaZ4/2FgT3F35IJVfVki/Kfv/cF1kjxx/ka43qIKd3OEnz OYSd0D+MUzpFUSRqh8uiUTRNjAgqdPF5kun9fp6XUEaQWHVhOONtBRs7igJUcvMgFnUP eZ3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QVD1gZDtb4fovFqzFSv9irG+x3sWgcFoSpx/oNvkoLE=; b=Mar2353qLjywFEqMed6M/bAkIMQs/neuvqbNRANw0D5sNePMTs4UESUtZ//T4QsDaH 5dDZI/bcknfmn0px5t6+WkVrf7pkde6y4YX2/rFRKSE9stEXE1BcDz1cW4TfjzFnx83b w/PkJeiVTNbjYjyrNoAk/DuDvLFt6LkxUx/t/Z1kcllLWLo8rfSUHlzIkVNY6nXCBK+b sMwKFbJm1bE+3jb/ylb3f1+fFEbSYO5knayesFxTwAVRXef/NGblxs3C0p7DW+NzMpHk e3d8qmQX9dXhvVrlfRewB91VtsD2ALg7Se/WTvgE0E92zjiZ7VT4nKi67Dvz6IfnhZ6Y wk8A== X-Gm-Message-State: AOAM533cq96wjI56DUKE8KMczDv07hctueS0IH4b2QfcCn2TeoPLDfVO 75Vj3PPWdxm0PfzywGZQ758bnW2lpPj1VJNWH0+vQg== X-Google-Smtp-Source: ABdhPJxxNqP9whJBEo8PXefOIUInGr92nmFnc34eTFWtLjjf5s45gth3jWS60mVcMNMD5wKHe5/WUmhmwWvm9MNerb8= X-Received: by 2002:a2e:541c:: with SMTP id i28mr1587321ljb.77.1599864031892; Fri, 11 Sep 2020 15:40:31 -0700 (PDT) MIME-Version: 1.0 References: <20200910022435.2773735-1-guro@fb.com> <20200910224309.GB1307870@carbon.dhcp.thefacebook.com> <20200911213402.GB1163084@carbon.dhcp.thefacebook.com> In-Reply-To: <20200911213402.GB1163084@carbon.dhcp.thefacebook.com> From: Shakeel Butt Date: Fri, 11 Sep 2020 15:40:20 -0700 Message-ID: Subject: Re: [PATCH] mm: memcg/slab: fix racy access to page->mem_cgroup in mem_cgroup_from_obj() To: Roman Gushchin Cc: Andrew Morton , Linux MM , Johannes Weiner , Michal Hocko , Kernel Team , LKML , Vlastimil Babka , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 6BBA637608 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000206, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Sep 11, 2020 at 2:34 PM Roman Gushchin wrote: > [snip] > > > > Also have you taken a look at [1]? I am still trying to figure out how > > that is possible. > > > > [1] https://lore.kernel.org/lkml/20200901075321.GL4299@shao2-debian/ > > Hm, yeah, it's complicated. At the very first glance it looks like that the > obj_cgroups vector is placed onto the very same page it describes, or at least > it shares the kmem_cache with it, with some bad consequences. Could be something > SLAB-specific, newer saw anything like that with SLUB. > Or maybe it's completely unrelated and has been attributed to this commit > by mistake. > > I've spent several hours running the provided test in a loop, but wasn't > lucky enough to trigger it. Did you try? > Yeah same, no success in reproducing it.