Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753406AbdFSTRg (ORCPT + 2 others); Mon, 19 Jun 2017 15:17:36 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:52289 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753258AbdFSSgQ (ORCPT ); Mon, 19 Jun 2017 14:36:16 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Michal Hocko , Tetsuo Handa , Al Viro , Andrew Morton , Linus Torvalds , Willy Tarreau Subject: [PATCH 3.10 140/268] mm, fs: check for fatal signals in do_generic_file_read() Date: Mon, 19 Jun 2017 20:30:39 +0200 Message-Id: <1497897167-14556-141-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1497897167-14556-1-git-send-email-w@1wt.eu> References: <1497897167-14556-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Michal Hocko commit 5abf186a30a89d5b9c18a6bf93a2c192c9fd52f6 upstream. do_generic_file_read() can be told to perform a large request from userspace. If the system is under OOM and the reading task is the OOM victim then it has an access to memory reserves and finishing the full request can lead to the full memory depletion which is dangerous. Make sure we rather go with a short read and allow the killed task to terminate. Link: http://lkml.kernel.org/r/20170201092706.9966-3-mhocko@kernel.org Signed-off-by: Michal Hocko Reviewed-by: Christoph Hellwig Cc: Tetsuo Handa Cc: Al Viro Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Willy Tarreau --- mm/filemap.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index 725a100..7213078 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1123,6 +1123,11 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, cond_resched(); find_page: + if (fatal_signal_pending(current)) { + error = -EINTR; + goto out; + } + page = find_get_page(mapping, index); if (!page) { page_cache_sync_readahead(mapping, -- 2.8.0.rc2.1.gbe9624a