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 EF153C76188 for ; Fri, 19 Jul 2019 04:02:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C592E21873 for ; Fri, 19 Jul 2019 04:02:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563508943; bh=UBqcQhmWL9gkiGqShZjWJ3U9ctduDaxKS9dB+e4OMVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KdTbiieIFxpI5lUzQnr1tCFxezO+EPvhXnv9FvNiSf0BmBikbiiR41CLYc2LjCfdF +C5TpF/5sYYaowL4oWP6X4MTtp/yJFe4xeHnhbOgLdZ2rObEIMUFdtD3YIeOoefaC5 q0cnn/GvDC4Gckcycsm18kcWLo4BmG8XZdQIENYE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729977AbfGSECW (ORCPT ); Fri, 19 Jul 2019 00:02:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:34100 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728140AbfGSECM (ORCPT ); Fri, 19 Jul 2019 00:02:12 -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 5897C21882; Fri, 19 Jul 2019 04:02:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563508931; bh=UBqcQhmWL9gkiGqShZjWJ3U9ctduDaxKS9dB+e4OMVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a4IZEAxcKMH6YjRWINICRFRdgh03+lm5kvzXcHJNJoC7ouXPXm8EsfNSWVI1yBOdS jEb3tvSWEnfaEIA4fMC3mzk5mrKRxsMjaxdGx6pRIiI7ewptIEQurDWqigGmvxKJJq BPGDSGvJ7hQqdemB2RGtd/VV45mIIsQpGXfTzj7I= 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 5.2 163/171] proc: use down_read_killable mmap_sem for /proc/pid/smaps_rollup Date: Thu, 18 Jul 2019 23:56:34 -0400 Message-Id: <20190719035643.14300-163-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190719035643.14300-1-sashal@kernel.org> References: <20190719035643.14300-1-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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 01d4eb0e6bd1..4d9a8e72d91f 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -828,7 +828,10 @@ 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) { @@ -845,8 +848,9 @@ 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