From patchwork Mon May 10 05:59:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hugh Dickins X-Patchwork-Id: 12246907 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=-24.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL autolearn=ham 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 00841C433B4 for ; Mon, 10 May 2021 05:59:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 676CC61421 for ; Mon, 10 May 2021 05:59:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 676CC61421 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 8C21E6B0070; Mon, 10 May 2021 01:59:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 870DF6B0071; Mon, 10 May 2021 01:59:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6C3496B0072; Mon, 10 May 2021 01:59:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0178.hostedemail.com [216.40.44.178]) by kanga.kvack.org (Postfix) with ESMTP id 4D1CE6B0070 for ; Mon, 10 May 2021 01:59:57 -0400 (EDT) Received: from smtpin32.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0782E180AD81A for ; Mon, 10 May 2021 05:59:57 +0000 (UTC) X-FDA: 78124270434.32.577EBBE Received: from mail-qt1-f171.google.com (mail-qt1-f171.google.com [209.85.160.171]) by imf01.hostedemail.com (Postfix) with ESMTP id D5F285001522 for ; Mon, 10 May 2021 05:59:53 +0000 (UTC) Received: by mail-qt1-f171.google.com with SMTP id f8so6999178qth.6 for ; Sun, 09 May 2021 22:59:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:user-agent:mime-version; bh=gaxObsy3YPrpH1zijJRXin726mARZtuqaRFKkyvziKI=; b=pp6jcXClHu0nYyzMGAXp5LKUOsjmgyHqUi5+9jQQQKNPMb21zGtoMW/DN00ZQqUtmn 5l345Dau66yXcvQrtPhJLApedSoxqqLLMqVjCW/hZyU0/lofgHcm6sV7IMSKJv/ql9zP 23G19FnwcNV0HeQxKlJQ7GCVWdtHFWPuC75UmMbvV1Ha/DifZahLDF4Wucc5UNAW89yG WBfxFHaAzhPnfERIrb8stdSCUXL+23OC7pA/V2DvsA4EfebMFxZ3X9i7RHQrKKPm3sLP 8hRay5SsiwEiSUCAu156gfqYoxEb7sZ3TBOvzLr4G5s5+8kdMp13pNj7fHMm0WvRKevd XoYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:user-agent :mime-version; bh=gaxObsy3YPrpH1zijJRXin726mARZtuqaRFKkyvziKI=; b=S6S+Hc2D3HzUTFSeuG941g1hAtj6KelAkhOWT1Ne8CMWTMWU25lG6nM+86ynQ+EAR1 X6HscHT3Q7Uu52zJToYLsvXIIM7l9wGl4FyU+Svw4qc0DguBgAXpxdhxclUYn4Latj13 ud9IfBSIp5tC0NcE6oAwzRbX0J3q/0MSrUTwhVXWsFxQ6SUdKliruWsV0As5H054Laes /0CeRjL1ZxkCKHBKrUfz2poBRJQH54wLYM5ClccItOyi+ZtjXSDkOhiTLPoghMeTUsB/ CXevi7hgDml+mLPl3/k8z5u9Wsbsb1XKpA/SkiNW7J5jdHaki0TbIcZ2uK3nP/HGcTx3 ajng== X-Gm-Message-State: AOAM531IVN/EJPf8k1IO3p9S8915kYjDQLqcE6ukTwG4RcpjaQ13kUyT 3IK1Bz/ZBLijJ/6+oOEadjyVTA== X-Google-Smtp-Source: ABdhPJw1BbXE6F7/fYsE6Dq/o366WPKxIbih8MadXG8ALLoaKhyTTrCiLr7i26XlphCkd+kEWT9VpQ== X-Received: by 2002:ac8:5810:: with SMTP id g16mr20453604qtg.135.1620626395819; Sun, 09 May 2021 22:59:55 -0700 (PDT) Received: from eggly.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id f7sm11951045qtm.41.2021.05.09.22.59.54 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Sun, 09 May 2021 22:59:55 -0700 (PDT) Date: Sun, 9 May 2021 22:59:34 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Andrew Morton cc: Hugh Dickins , Miaohe Lin , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH] ksm: Revert "use GET_KSM_PAGE_NOLOCK to get ksm page in remove_rmap_item_from_tree()" Message-ID: User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: D5F285001522 Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=pp6jcXCl; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf01.hostedemail.com: domain of hughd@google.com designates 209.85.160.171 as permitted sender) smtp.mailfrom=hughd@google.com X-Stat-Signature: x5j5c7t9cpwz4aqafozawbapzkeyqhia Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=mail-qt1-f171.google.com; client-ip=209.85.160.171 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620626393-593450 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: This reverts commit 3e96b6a2e9ad929a3230a22f4d64a74671a0720b. General Protection Fault in rmap_walk_ksm() under memory pressure: remove_rmap_item_from_tree() needs to take page lock, of course. Signed-off-by: Hugh Dickins --- mm/ksm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- 5.13-rc1/mm/ksm.c 2021-05-09 17:03:44.010422188 -0700 +++ linux/mm/ksm.c 2021-05-09 22:12:39.403008350 -0700 @@ -776,11 +776,12 @@ static void remove_rmap_item_from_tree(s struct page *page; stable_node = rmap_item->head; - page = get_ksm_page(stable_node, GET_KSM_PAGE_NOLOCK); + page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK); if (!page) goto out; hlist_del(&rmap_item->hlist); + unlock_page(page); put_page(page); if (!hlist_empty(&stable_node->hlist))