From patchwork Thu May 5 12:45:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hyeonggon Yoo <42.hyeyoo@gmail.com> X-Patchwork-Id: 12839525 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 115C4C433EF for ; Thu, 5 May 2022 12:45:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 15CD46B0071; Thu, 5 May 2022 08:45:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 10B0B6B0073; Thu, 5 May 2022 08:45:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F149F6B0074; Thu, 5 May 2022 08:45:27 -0400 (EDT) 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 E29C96B0071 for ; Thu, 5 May 2022 08:45:27 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id 90DF981EAD for ; Thu, 5 May 2022 12:45:27 +0000 (UTC) X-FDA: 79431660294.28.367B72E Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) by imf01.hostedemail.com (Postfix) with ESMTP id 041F740099 for ; Thu, 5 May 2022 12:45:17 +0000 (UTC) Received: by mail-pl1-f172.google.com with SMTP id j14so4286500plx.3 for ; Thu, 05 May 2022 05:45:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=F7HMG+OVhPOos/cU+pyZ4Uh+EgyQ7cM2dbYtA5UL2Io=; b=FliSKDjWtBxb7sHTcZuxqXvrzycO2HY1qnLgfgN0JxJBZoqrNfUBaMen+TDkvlhUV4 nNH1yczPMbCbdQZszx01TxDN5R7CYc0/qpex13veQqYJbnKd6pn7F+z+Hi+v1bcUjBzw dixZ2W+1YVmTRjlHGNp00kV6lcMaZyqV9eKWK1ItGE2jfGzJs85k2PEQkSoNnVUnyR/w ik39nS88yAb6Jqw8TBRsY/SUWdjGjLKhCCamMrkmzcC75UyK6WT1eKLZ0pgjTF21uu5x EdcoHsuaZaAyaEcdonRTWtd4ia7oxAdlGICgPpLUGzkvTtOiwwJ/cUJyBPx8Kof5NhhN BEtw== 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:mime-version :content-disposition; bh=F7HMG+OVhPOos/cU+pyZ4Uh+EgyQ7cM2dbYtA5UL2Io=; b=jvA3TflYDV/LYkL83PaRMehHUx64cV3vYtDF+hRNCbnsJrMZE2rvKt7QqoJuVZxMHY PGgxGEseBnMZFmOtcq3jWHQTjHbrrPYczztH7XXI2rdOUxw8sqOMPuaB0u7uv6QBFD3x Lpb+sFzQfUgycKsuBa8Tf2aS6V3c6cQkN1mB6ynoxSxbSPa/ZPqvlPM1UpZl7oygAbPx Fp197mNqe3ChKLPwjRKAeAHio3t8rgCRL0VPRvlf3cMzOQVQhEgLy0VkMZvllTfa7ref y8BVxwXaO3Vx8dWG6oYycn9/bE/c+uriW92HRQlluPn9Meg1gcg8Ae4ilGbos4UJOy70 c9CQ== X-Gm-Message-State: AOAM531hb4sXDquXlVihBFqwZWcOp1W8cw8HmlzMv4lLC6Iw5FH1jvWT pva0bkxKdRS3xo+ZTq7zfHc= X-Google-Smtp-Source: ABdhPJzwQrMHYTwtniSHPVkeMU50/jRdLb4QENkxiLwIbU63QlDYPWoRGcR7d0QfrhaLzXg99SB6Aw== X-Received: by 2002:a17:903:40c2:b0:15c:fd2a:7198 with SMTP id t2-20020a17090340c200b0015cfd2a7198mr22407514pld.0.1651754725679; Thu, 05 May 2022 05:45:25 -0700 (PDT) Received: from hyeyoo ([114.29.24.243]) by smtp.gmail.com with ESMTPSA id jf20-20020a17090b175400b001d6510cbbaesm5230422pjb.46.2022.05.05.05.45.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 May 2022 05:45:25 -0700 (PDT) Date: Thu, 5 May 2022 21:45:18 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Marco Elver Cc: Muchun Song , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hyeonggon Yoo <42.hyeyoo@gmail.com> Subject: [PATCH v4] mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool Message-ID: MIME-Version: 1.0 Content-Disposition: inline X-Rspamd-Queue-Id: 041F740099 X-Stat-Signature: ikm5pd81fwkbtf3nxrhhk46gm8zsgr3r Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=FliSKDjW; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf01.hostedemail.com: domain of 42.hyeyoo@gmail.com designates 209.85.214.172 as permitted sender) smtp.mailfrom=42.hyeyoo@gmail.com X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1651754717-259232 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: 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> Reviewed-by: Marco Elver Reviewed-by: Muchun Song --- v3 -> v4: - Use struct slab instead of folio and reset memcg_data and clear PG_slab only if PG_slab flag is set (virt_to_slab() != NULL). Thanks Muchun. Now it looks much better and still works. - Remove Reviewed-by: tags as the code changed. Please add new one if the patch still looks good to you. mm/kfence/core.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/mm/kfence/core.c b/mm/kfence/core.c index a203747ad2c0..58dfac1828ce 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -642,6 +642,16 @@ 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 slab *slab = virt_to_slab(p); + + if (!slab) + continue; +#ifdef CONFIG_MEMCG + slab->memcg_data = 0; +#endif + __folio_clear_slab(slab_folio(slab)); + } memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool)); __kfence_pool = NULL; return false;