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 X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS autolearn=unavailable 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 3035BC04E53 for ; Wed, 15 May 2019 08:41:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 02A1C2089E for ; Wed, 15 May 2019 08:41:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="bJzcjZX6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726338AbfEOIlR (ORCPT ); Wed, 15 May 2019 04:41:17 -0400 Received: from forwardcorp1j.mail.yandex.net ([5.45.199.163]:56816 "EHLO forwardcorp1j.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725871AbfEOIlQ (ORCPT ); Wed, 15 May 2019 04:41:16 -0400 Received: from mxbackcorp1o.mail.yandex.net (mxbackcorp1o.mail.yandex.net [IPv6:2a02:6b8:0:1a2d::301]) by forwardcorp1j.mail.yandex.net (Yandex) with ESMTP id 917962E14C0; Wed, 15 May 2019 11:41:13 +0300 (MSK) Received: from smtpcorp1j.mail.yandex.net (smtpcorp1j.mail.yandex.net [2a02:6b8:0:1619::137]) by mxbackcorp1o.mail.yandex.net (nwsmtp/Yandex) with ESMTP id 7l8bZ6vz9S-fD0GwFgT; Wed, 15 May 2019 11:41:13 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1557909673; bh=on37xMtDHf4i5spIW0sgEiVZh+kGUSg0VAm5Sv46Das=; h=Message-ID:Date:To:From:Subject:Cc; b=bJzcjZX6IIAUCNZqdyJas7Z7fGK9P92gcfgKNFGVYrbxnXDJ17C82J8LRWdyyAtHl EqAUj/W8BAy4Hpaw7JwRetWb/oFU2VFVtGgph3dPKN16Nxj069xSvJi4qjWeh07zl9 r+h/pSCIwWSvsMqVdHCAPlw4g0drkv+mbzc+HnWY= Authentication-Results: mxbackcorp1o.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-red.dhcp.yndx.net (dynamic-red.dhcp.yndx.net [2a02:6b8:0:40c:ed19:3833:7ce1:2324]) by smtpcorp1j.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id dM2CepgjQa-fC8SnGfC; Wed, 15 May 2019 11:41:12 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Subject: [PATCH 1/5] proc: use down_read_killable for /proc/pid/maps From: Konstantin Khlebnikov To: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org Cc: Cyrill Gorcunov , Kirill Tkhai , Al Viro Date: Wed, 15 May 2019 11:41:12 +0300 Message-ID: <155790967258.1319.11531787078240675602.stgit@buzz> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Do not stuck forever if something wrong. This function also used for /proc/pid/smaps. Signed-off-by: Konstantin Khlebnikov --- fs/proc/task_mmu.c | 6 +++++- fs/proc/task_nommu.c | 6 +++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 01d4eb0e6bd1..2bf210229daf 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -166,7 +166,11 @@ static void *m_start(struct seq_file *m, loff_t *ppos) if (!mm || !mmget_not_zero(mm)) return NULL; - down_read(&mm->mmap_sem); + if (down_read_killable(&mm->mmap_sem)) { + mmput(mm); + return ERR_PTR(-EINTR); + } + hold_task_mempolicy(priv); priv->tail_vma = get_gate_vma(mm); diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index 36bf0f2e102e..7907e6419e57 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -211,7 +211,11 @@ static void *m_start(struct seq_file *m, loff_t *pos) if (!mm || !mmget_not_zero(mm)) return NULL; - down_read(&mm->mmap_sem); + if (down_read_killable(&mm->mmap_sem)) { + mmput(mm); + return ERR_PTR(-EINTR); + } + /* start from the Nth VMA */ for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) if (n-- == 0)