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 126EBC433EF for ; Thu, 5 May 2022 10:54:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 583096B0071; Thu, 5 May 2022 06:54:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5313A6B0073; Thu, 5 May 2022 06:54:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3D12A6B0074; Thu, 5 May 2022 06:54:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 2E1E66B0071 for ; Thu, 5 May 2022 06:54:25 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id F314261903 for ; Thu, 5 May 2022 10:54:24 +0000 (UTC) X-FDA: 79431380490.03.C4DFEF4 Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) by imf02.hostedemail.com (Postfix) with ESMTP id 4BF7380087 for ; Thu, 5 May 2022 10:54:18 +0000 (UTC) Received: by mail-pj1-f54.google.com with SMTP id iq10so3885386pjb.0 for ; Thu, 05 May 2022 03:54:23 -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=0goD14Q1e/CsgbECNnLR7yDE1KrrNCX6z5lnWWhtC+8=; b=zHk/g7TJ6/WF8TlubpawAkRyttxAK4JOj/oucV1uu/VJt3BWVNbj/am/Ee5e+YmrIF ZUu7WPyc/uGl95YsITpFgvBYMu4kUAPGHRu/nrGbvOH7Rhgf8L5YqmnzEI4wjTFBnpIp W7J2rjOQ1Bbe/VijvOMAHx+3my5uxQlJDzXhlGV9A1bUyzxL+iTfqVeKNL/Hl7xWWTUj ITgr0XOepz0AqJKWZn7WmkQk/YkUglEHSqbplJ49QZ1jPIPr5tw2pHO0J8hy+Kc42U+K 0/pxA0szWAdevPNGnjUljmrkE7UQKOpZkae5GZAGqcQ/nVpzfn/CF3rWFhUeJhR3C/04 qnew== 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=0goD14Q1e/CsgbECNnLR7yDE1KrrNCX6z5lnWWhtC+8=; b=hatYBxqfqp4ac4Kj7Sd67F8txBCXmu3mBEwu/QDvvuZ0lbQjrToEm7GIGbiueP0FCr f0uArdhJglQ8XthYWQOvuwPR2AOKhPFmO2dFdyBcvEcd+8m0rURlQrRUnUsM6DkGOW0F z12mTlLVTJDM2r3KhE0b56xA5lK737tppnlsZe2cacxwMqZhjTitx78cX8t/eynv8UwI 7PdtvASJL+/2+CaDdGhw1zvCjtIz4U4OZRvMoXTjpFPCma5nA+dP+eNay/3NuRcRHDSk VNtIHvg4mdBbe1W6gkPACQryJr5jyjHwFvUB5e9JIgA8MHpXxSXDJATVaCygMFxLf6Uw /8DA== X-Gm-Message-State: AOAM530B5jRgfhPSuYfkjCQ5IjsznXwmtYcuNY/QGhwNUtwh9hwdZNSe 6o7vd1OoQQx7Rb0g2pn/yNvBKw== X-Google-Smtp-Source: ABdhPJzNVqmW8bCjPVkalYOgID+2aRbODpiJd6bGg8bopO4SSb17YHiEC0pa6zl+N4/OKoTzcHPqlw== X-Received: by 2002:a17:90b:350d:b0:1dc:6680:6f1d with SMTP id ls13-20020a17090b350d00b001dc66806f1dmr5344660pjb.27.1651748062717; Thu, 05 May 2022 03:54:22 -0700 (PDT) Received: from localhost ([139.177.225.234]) by smtp.gmail.com with ESMTPSA id d5-20020a170902728500b0015e8d4eb22asm1226760pll.116.2022.05.05.03.54.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 May 2022 03:54:22 -0700 (PDT) Date: Thu, 5 May 2022 18:54:18 +0800 From: Muchun Song To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool Message-ID: References: <20220505073920.1880661-1-42.hyeyoo@gmail.com> <20220505101337.1997819-1-42.hyeyoo@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220505101337.1997819-1-42.hyeyoo@gmail.com> X-Rspamd-Queue-Id: 4BF7380087 X-Stat-Signature: t3bx191nspt7od6a9gr8pg5zp1zgscu1 Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b="zHk/g7TJ"; dmarc=pass (policy=none) header.from=bytedance.com; spf=pass (imf02.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.216.54 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1651748058-800239 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 Thu, May 05, 2022 at 07:13:37PM +0900, Hyeonggon Yoo wrote: > When kfence fails to initialize kfence pool, it frees the pool. > But it does not reset PG_slab flag and memcg_data of struct page. > > Below is a BUG because of this. Let's fix it by resetting PG_slab > and memcg_data 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> > Reviewed-by: Marco Elver > Reviewed-by: Muchun Song > --- > > v2 -> v3: > - Add Reviewed-by: tags from Marco and Muchun. Thanks! > - Initialize folio where it is defined. > > mm/kfence/core.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index a203747ad2c0..b7d3a9667f00 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -642,6 +642,14 @@ static bool __init kfence_init_pool_early(void) > * fails for the first page, and therefore expect addr==__kfence_pool in > * most failure cases. > */ > + for (char *p = (char *)addr; p < __kfence_pool + KFENCE_POOL_SIZE; p += PAGE_SIZE) { > + struct folio *folio = virt_to_folio(p); > + After more thinking, I think it is better to use 'struct slab *' to define a local variable since we already use this struct throughout slab core. What do you think? Thanks. > + __folio_clear_slab(folio); > +#ifdef CONFIG_MEMCG > + folio->memcg_data = 0; > +#endif > + } > memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool)); > __kfence_pool = NULL; > return false; > -- > 2.32.0 > >