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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 407C2C76196 for ; Fri, 19 Jul 2019 04:07:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1ACC1218A6 for ; Fri, 19 Jul 2019 04:07:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509239; bh=N/5pqSiiXwOnxmp2JUZnyCLui6ditF4vINIRb5HKCPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uUg+CnkDaR8e1eDB+zPyiGNqi7wUebF5m1E+x8l6rPgkYt6HHGb8kFaVrswzEOOvK NL0iRRstP6rz4HfELYNE3H6iuL09XgqEqwP7CDJa+RNG8PWhUVMx5zyfOTZbpTv0Tn VpWNy3nGfgYGdy2DV5/LP+9g4DNVXIoTFN31mMXo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732639AbfGSEHR (ORCPT ); Fri, 19 Jul 2019 00:07:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:40852 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732626AbfGSEHR (ORCPT ); Fri, 19 Jul 2019 00:07:17 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8AF8B21849; Fri, 19 Jul 2019 04:07:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509236; bh=N/5pqSiiXwOnxmp2JUZnyCLui6ditF4vINIRb5HKCPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L9ik2o/sSFZsEm2Vl8zDrR0NjfKqLkPOCr2ntVfmxj9HmSLsDq7JqiwBKBxXxgYl/ J4kMp7fsnj0B2ye+v0DvGrF7UcOg+kBvsNZ/J6nFHZfSsqQfef9QqUNU5ZTLvtN9Hx gFB62opJiT+v96FqFjFZaDGS0eLgWWjKtzWtlsCo= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Konstantin Khlebnikov , Roman Gushchin , Cyrill Gorcunov , Kirill Tkhai , Michal Hocko , Alexey Dobriyan , Al Viro , Matthew Wilcox , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Oleg Nesterov , Andrew Morton , Linus Torvalds , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 5.1 138/141] proc: use down_read_killable mmap_sem for /proc/pid/maps Date: Fri, 19 Jul 2019 00:02:43 -0400 Message-Id: <20190719040246.15945-138-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190719040246.15945-1-sashal@kernel.org> References: <20190719040246.15945-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Konstantin Khlebnikov [ Upstream commit 8a713e7df3352b8d9392476e9cf29e4e185dac32 ] Do not remain stuck forever if something goes wrong. Using a killable lock permits cleanup of stuck tasks and simplifies investigation. This function is also used for /proc/pid/smaps. Link: http://lkml.kernel.org/r/156007493160.3335.14447544314127417266.stgit@buzz Signed-off-by: Konstantin Khlebnikov Reviewed-by: Roman Gushchin Reviewed-by: Cyrill Gorcunov Reviewed-by: Kirill Tkhai Acked-by: Michal Hocko Cc: Alexey Dobriyan Cc: Al Viro Cc: Matthew Wilcox Cc: Michal Koutný Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- 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 d544ab2e4210..d416657bfbb7 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) -- 2.20.1