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,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 D249CC76188 for ; Fri, 19 Jul 2019 04:12:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A93EC218E0 for ; Fri, 19 Jul 2019 04:12:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509562; bh=Fd/iL7k9ygEDKTPyKwsLZ60pZjcdmHPKdB8B+q4aVFQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ylklr5o/X6ftt33LBKdvKxegbhXcLArmwvXZcyyN7u5o0M6Ql7tP760fluiGrp1qb OCsKlYM+/DJtGED8g2YX/r82jq/yUpezsTHbNkIajOCCl8Hxsq1mG6P0LoA73Mti4a qubnHKdfiJXPjr1au7CHBZs1QBKFyyl/sRwusZow= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732885AbfGSEMl (ORCPT ); Fri, 19 Jul 2019 00:12:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:45526 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388249AbfGSEKp (ORCPT ); Fri, 19 Jul 2019 00:10:45 -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 6B1B421873; Fri, 19 Jul 2019 04:10:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509444; bh=Fd/iL7k9ygEDKTPyKwsLZ60pZjcdmHPKdB8B+q4aVFQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sTozd/R7hY/A7Edx9cFkZMuWZdvJhoDLPUYpbmJ50TRAl1aHSdQHNdzBSV4sE7I14 z/AzK2O9VixSD5JhtRiACuJcHGnbJ/1hImxhxjKRo5sNOlabvjrYxTRJM0hAYZKsRs YE3YDXWqJIslh1sF82JDWj7RWXWsyuUNdgn1BFw0= 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 4.19 094/101] proc: use down_read_killable mmap_sem for /proc/pid/smaps_rollup Date: Fri, 19 Jul 2019 00:07:25 -0400 Message-Id: <20190719040732.17285-94-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 a26a97815548574213fd37f29b4b78ccc6d9ed20 ] Do not remain stuck forever if something goes wrong. Using a killable lock permits cleanup of stuck tasks and simplifies investigation. Link: http://lkml.kernel.org/r/156007493429.3335.14666825072272692455.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 | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index c5819baee35c..b2010055180e 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -826,7 +826,10 @@ static int show_smaps_rollup(struct seq_file *m, void *v) memset(&mss, 0, sizeof(mss)); - down_read(&mm->mmap_sem); + ret = down_read_killable(&mm->mmap_sem); + if (ret) + goto out_put_mm; + hold_task_mempolicy(priv); for (vma = priv->mm->mmap; vma; vma = vma->vm_next) { @@ -843,8 +846,9 @@ static int show_smaps_rollup(struct seq_file *m, void *v) release_task_mempolicy(priv); up_read(&mm->mmap_sem); - mmput(mm); +out_put_mm: + mmput(mm); out_put_task: put_task_struct(priv->task); priv->task = NULL; -- 2.20.1