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 5A551C433F5 for ; Tue, 8 Mar 2022 18:07:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349380AbiCHSI2 (ORCPT ); Tue, 8 Mar 2022 13:08:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241141AbiCHSIZ (ORCPT ); Tue, 8 Mar 2022 13:08:25 -0500 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C632B4C for ; Tue, 8 Mar 2022 10:07:26 -0800 (PST) Received: by mail-pj1-x1029.google.com with SMTP id cx5so75059pjb.1 for ; Tue, 08 Mar 2022 10:07:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=pZliwmLm6S8tya/djJ5W/U/prHZbfOKsGwUj10OUIn0=; b=qpLtvuz0mEEMCmqJCiWKhn+xCPGesu6Pw3r09ZrgwzSL8mgKdriqPFXA9ih3Is4h9B SifskdlThgG6P5akCPbbqD9WE7XCGeo4X4REI2Xq16nnqJdjDh8Yg44L1Hb1N4TfG6tu n8UWwRuJGdgXt61SgxTM6sWov7sUP9PoJ1F6PcjaHjk4UA0ohjNiNuIFjIo8aiJ89BkM q1SFa5D5qa67somAsAgHXMVzggWN2AB2F3C/pooif71T2zLOfB4AZ8cqgO3NM+UdycIN 16Jx9ckYs0lUPqmnO2OwYbtPAh5PCfrByZLDoRJaA15JjjaLtO055sKJPEXWxnVf+m35 QGtw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=pZliwmLm6S8tya/djJ5W/U/prHZbfOKsGwUj10OUIn0=; b=S/eCHvnY7+K2/dzecnVuBVFhje3xZ7SFmwxV9GolhObQpfB1vDmncsACPeGM65FWy5 lHCuuE1JxDZ9Qcvjmkd/N3yjPBjdMqtTXrFcGapSzHyGszKJjACHhHVTsBFT5rLQ+S6E hZSndtcP5L6HZcqyVIYInvmPt7j5zGOjSOy4DH6HWKQoZAAlnTXhNdwRWr8ZO+UekYGX Kj6hFFJicN30tOHLm5jyPkkM5BB/6zLvbhkFcjq1oFcYqFaBYTVIlYgBhPkpI4TrvpZa xxh8kUR8oCZbvWo+3ow0IkessBtZ6JR4N/i63m9Dyha/HA2yflRdBhTGZs4RBQbzG3fn ZKdA== X-Gm-Message-State: AOAM53132LVStY8VuRf9Wu0na2eJWMSlyh2OvIVTZ4BL5a61cUO/SdO3 zNb2Fql8Wlt2TTCXKyOIVJs= X-Google-Smtp-Source: ABdhPJylFJEOWSaFFgHfIMPZ6Bg5gHKwdPIYqmxkknGO1e/TOEnJ+yqMzsCzV6dq5xLXIanBNwhu/g== X-Received: by 2002:a17:902:758f:b0:14f:b5ee:cc5a with SMTP id j15-20020a170902758f00b0014fb5eecc5amr18930620pll.43.1646762846012; Tue, 08 Mar 2022 10:07:26 -0800 (PST) Received: from bbox-1.mtv.corp.google.com ([2620:15c:211:201:ec3e:a6ab:7b5b:ed81]) by smtp.gmail.com with ESMTPSA id x23-20020a63fe57000000b0036490068f12sm15462368pgj.90.2022.03.08.10.07.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Mar 2022 10:07:12 -0800 (PST) Sender: Minchan Kim From: Minchan Kim To: Andrew Morton Cc: linux-mm , LKML , Chris Goldsworthy , Marcelo Tosatti , John Dias , Minchan Kim Subject: [PATCH] mm: fs: fix lru_cache_disabled race in bh_lru Date: Tue, 8 Mar 2022 10:07:09 -0800 Message-Id: <20220308180709.2017638-1-minchan@kernel.org> X-Mailer: git-send-email 2.35.1.616.g0bdcbb4464-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Check lru_cache_disabled under bh_lru_lock. Otherwise, it could introduce race below and it fails to migrate pages containing buffer_head. CPU 0 CPU 1 bh_lru_install lru_cache_disable lru_cache_disabled = false atomic_inc(&lru_disable_count); invalidate_bh_lrus_cpu of CPU 0 bh_lru_lock __invalidate_bh_lrus bh_lru_unlock bh_lru_lock install the bh bh_lru_unlock Fixes: 8cc621d2f45d (mm: fs: invalidate BH LRU during page migration) Signed-off-by: Minchan Kim --- fs/buffer.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 8e112b6bd371..c76a8ef60a75 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1235,16 +1235,18 @@ static void bh_lru_install(struct buffer_head *bh) int i; check_irqs_on(); + bh_lru_lock(); + /* * the refcount of buffer_head in bh_lru prevents dropping the * attached page(i.e., try_to_free_buffers) so it could cause * failing page migration. * Skip putting upcoming bh into bh_lru until migration is done. */ - if (lru_cache_disabled()) + if (lru_cache_disabled()) { + bh_lru_unlock(); return; - - bh_lru_lock(); + } b = this_cpu_ptr(&bh_lrus); for (i = 0; i < BH_LRU_SIZE; i++) { -- 2.35.1.616.g0bdcbb4464-goog