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=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 E9281C76196 for ; Fri, 19 Jul 2019 04:11:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C3C3221873 for ; Fri, 19 Jul 2019 04:11:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509468; bh=wG5lX/CmKxmM9lBvxU1b+LV4/KVMw8c0YZm9V9g76q8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uCwCxEWbosnvTWJrW4PUgK9fYSo6Oc7QGL4bBPA8ijoZ9ERaX28QBxzTnNy/cjgE2 XpI3K6Xlp49c4G01t1PKUOCWsAa8jgdDkZZ8zoSDMBM53U+/rcuQp6gNGk1qLIgTaO SaaFRTO2f9JTW4qa6Bs0feA9LxwaK+I0qQrAnSAI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388291AbfGSELH (ORCPT ); Fri, 19 Jul 2019 00:11:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:45824 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388247AbfGSELC (ORCPT ); Fri, 19 Jul 2019 00:11:02 -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 40BAD218E2; Fri, 19 Jul 2019 04:11:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509461; bh=wG5lX/CmKxmM9lBvxU1b+LV4/KVMw8c0YZm9V9g76q8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QqlFVXuCq2blgMWRQXBBzRFLC7papAXjacFjfBiG6SebuMHzGuCQZX8wjK6diEj47 vEY2cE8FfOEmKRF3p2zFwE1U1mf/zQ1EMXabmGjaTzIPhbO77yd6l3sJaskc/IsbDZ tNeRRs0hPea8OunPV6R1z7eCGKqvAXt0G+6x0774= 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 4.19 099/101] proc: use down_read_killable mmap_sem for /proc/pid/maps Date: Fri, 19 Jul 2019 00:07:30 -0400 Message-Id: <20190719040732.17285-99-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190719040732.17285-1-sashal@kernel.org> References: <20190719040732.17285-1-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 195fbbaf77d4..71aba44c4fa6 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 0b63d68dedb2..5161894a6d62 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