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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 056FAC433FF for ; Mon, 29 Jul 2019 19:43:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C632020C01 for ; Mon, 29 Jul 2019 19:43:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429414; bh=3lizOSZSapAncVFPDk5SecML46iwtuSEJnnXCAzjas0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AcBtQqipNib4JmmrzORVCka1MwzBwGYhqgGfnKcGmvhp/gTEp5Z7PzajsMiBa/Sdv Cql6hPYs0SYLtO4GyCVYViLq6Rjarkk3W7dJS7VU3lGjpEbBGE6wZr2jeRDM7mxhu/ G+a1Rfa6VuufKZuHRU3Sv6I/I0ThiVgp01IXeomk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389672AbfG2Tnd (ORCPT ); Mon, 29 Jul 2019 15:43:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:59832 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389657AbfG2Tna (ORCPT ); Mon, 29 Jul 2019 15:43:30 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D32C2205F4; Mon, 29 Jul 2019 19:43:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429409; bh=3lizOSZSapAncVFPDk5SecML46iwtuSEJnnXCAzjas0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PwNRXekieHW8Ac57KKNAG5jNWExGzTKvt5OpKgaldt19nnLPDT2xLmyphhd4km4G7 vBhNGYmr1qDKrKP1knA7IqTxA/lg9IlMOqsVbDShEYa0U9tqjJv8YsK6MBKJSbYVDu rSC9Y4Jak6E+d+I8GqHc8upsheEIpZzpHNSm6ARg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, 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 Subject: [PATCH 4.19 089/113] proc: use down_read_killable mmap_sem for /proc/pid/smaps_rollup Date: Mon, 29 Jul 2019 21:22:56 +0200 Message-Id: <20190729190716.728939574@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190655.455345569@linuxfoundation.org> References: <20190729190655.455345569@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ 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