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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22C40C433EF for ; Thu, 5 May 2022 14:06:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380447AbiEEOKV (ORCPT ); Thu, 5 May 2022 10:10:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380450AbiEEOKS (ORCPT ); Thu, 5 May 2022 10:10:18 -0400 Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E58DD44A19 for ; Thu, 5 May 2022 07:06:36 -0700 (PDT) Received: by mail-pg1-x531.google.com with SMTP id t13so3710063pgn.8 for ; Thu, 05 May 2022 07:06:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Q2ljtViJ97MO8Fx257qphwHt+nQ75TNnUf7PUXRqZ2w=; b=aOqVKnxxHjfkSNNgo6dj5GOX2bAnYy0by0tdOKMfYjFbgycrfiKPTwxwN1MUesuXpd Cd59l4npDzVpoxEUGc/CsE75OtHmFyiOsdCpUnF6ucK+EOQJbIGMNpSbDpnqfdulYYmj CZBBBQ4phmsavwma1uOMH1scQdFF+Qwm1CZDoCgUc1/HXorv7AqJSM0/jrNppluwT62k 6EGnB9xAnfmOid66q/w83ckrkWDRj6yniG2HEtcH5x0A1OwXGRqlv+l5C3zLXzi1e1h1 PlAI9ijpLeAToeMi2imNIX2jliyQicYyNSB88OqqIJvWylKlGB4oBeIlJ71XQrBL+0Tn uRPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Q2ljtViJ97MO8Fx257qphwHt+nQ75TNnUf7PUXRqZ2w=; b=zahV98fyWt/MAfiVu6pzER+Q0Tn+YkDtFSes6yPWUXsBOZqFz8YB7VJAqRKjrfyFwA hR4zDCeA+3I1p1HxLrxJIK/Z0B1EywodzRnY2y6e7mCctW+znVb05P8+85kNQ9ER35Qt 5baVsG3Ep/xFO4XFwZBTd0u2JyDX+oo3zo4o8mv5CRt9XK6pn1v2vSybYpHRHeplaiCr F9rjvi0rXN7xf7nYSUv1aI87nsUz1mRXMtcNKRP0coCxEtB5dob9xI1ySor4U6CQFir1 DpPMDQPeaejUu2TBkjnPRoQB8pczfdYDdDZkvhjzBe3iakv3XDV7c7h2Ept2k5WkaDaA OdQw== X-Gm-Message-State: AOAM533FP8JvPQY0I68rT/nKMOq6CSVRAatgu5/T96St+di3veaGv9kQ 6FHPDEMkzgVXggqEn0nrecs7Sqr/LIayBg== X-Google-Smtp-Source: ABdhPJxrGj5lRIZdvSqmPTjoHxM6GE1WuxbKRCnPdk5AEc1NL/F2SsECH09Pl7Da4LnsHVdqpNeUpg== X-Received: by 2002:a05:6a00:248d:b0:510:5d7d:18ab with SMTP id c13-20020a056a00248d00b005105d7d18abmr3713300pfv.51.1651759596369; Thu, 05 May 2022 07:06:36 -0700 (PDT) Received: from localhost ([2408:8207:18da:2310:717f:b863:7c3d:2306]) by smtp.gmail.com with ESMTPSA id m17-20020aa79011000000b0050dc7628177sm1410071pfo.81.2022.05.05.07.06.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 May 2022 07:06:36 -0700 (PDT) Date: Thu, 5 May 2022 22:06:33 +0800 From: Muchun Song To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Marco Elver , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 05, 2022 at 09:45:18PM +0900, Hyeonggon Yoo wrote: > When kfence fails to initialize kfence pool, it frees the pool. > But it does not reset memcg_data and PG_slab flag. > > Below is a BUG because of this. Let's fix it by resetting memcg_data > and PG_slab flag before free. > > [ 0.089149] BUG: Bad page state in process swapper/0 pfn:3d8e06 > [ 0.089149] page:ffffea46cf638180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d8e06 > [ 0.089150] memcg:ffffffff94a475d1 > [ 0.089150] flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff) > [ 0.089151] raw: 0017ffffc0000200 ffffea46cf638188 ffffea46cf638188 0000000000000000 > [ 0.089152] raw: 0000000000000000 0000000000000000 00000000ffffffff ffffffff94a475d1 > [ 0.089152] page dumped because: page still charged to cgroup > [ 0.089153] Modules linked in: > [ 0.089153] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B W 5.18.0-rc1+ #965 > [ 0.089154] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 > [ 0.089154] Call Trace: > [ 0.089155] > [ 0.089155] dump_stack_lvl+0x49/0x5f > [ 0.089157] dump_stack+0x10/0x12 > [ 0.089158] bad_page.cold+0x63/0x94 > [ 0.089159] check_free_page_bad+0x66/0x70 > [ 0.089160] __free_pages_ok+0x423/0x530 > [ 0.089161] __free_pages_core+0x8e/0xa0 > [ 0.089162] memblock_free_pages+0x10/0x12 > [ 0.089164] memblock_free_late+0x8f/0xb9 > [ 0.089165] kfence_init+0x68/0x92 > [ 0.089166] start_kernel+0x789/0x992 > [ 0.089167] x86_64_start_reservations+0x24/0x26 > [ 0.089168] x86_64_start_kernel+0xa9/0xaf > [ 0.089170] secondary_startup_64_no_verify+0xd5/0xdb > [ 0.089171] > > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") > Fixes: 8f0b36497303 ("mm: kfence: fix objcgs vector allocation") > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > Thanks for your work on this. Reviewed-by: Muchun Song