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 6AFDFC76195 for ; Fri, 19 Jul 2019 04:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 444E3218A6 for ; Fri, 19 Jul 2019 04:02:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563508964; bh=AsWeCu7Nx+RB8vYcUFehf/VOmlzRRWN98qdGTaeI180=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TZXNFmPg/A5DhbMtpCj9cOV+qK67dHA3/UlZOJgCr1nfPKLS1WeQNBfGUyKHDKhDL 8OirVmJ1HsO/TBM+G4Q5qZiewjpuuayI7FsXOBxdR/28buo02CU/waAfvyHmExJXxb zuu3NHd9+hnIPlpMSYUXF7aGsMAneYP7N9ro9lCg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729998AbfGSECY (ORCPT ); Fri, 19 Jul 2019 00:02:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:34248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729926AbfGSECT (ORCPT ); Fri, 19 Jul 2019 00:02:19 -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 8B79421851; Fri, 19 Jul 2019 04:02:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563508938; bh=AsWeCu7Nx+RB8vYcUFehf/VOmlzRRWN98qdGTaeI180=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QdKGf8EQldXu2w+Ahhtf3gB0DSh4c19pJx3VLNrxwYDiZdsgY7+K8ruHA8J/sASpW dou3qAaNDhc8jQU3VpRNo0h+WYOn+q62gE4SQvkAXy7+9khAMIGl7rBKDg5YmOm5aO gpV/7UPvJrCN0cq48ZdA/fcFWBNfCLoRSXcH71yA= 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 5.2 165/171] proc: use down_read_killable mmap_sem for /proc/pid/clear_refs Date: Thu, 18 Jul 2019 23:56:36 -0400 Message-Id: <20190719035643.14300-165-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 c46038017fbdcac627b670c9d4176f1d0c2f5fa3 ] Do not remain stuck forever if something goes wrong. Using a killable lock permits cleanup of stuck tasks and simplifies investigation. Replace the only unkillable mmap_sem lock in clear_refs_write(). Link: http://lkml.kernel.org/r/156007493826.3335.5424884725467456239.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 | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 1d9c63cd8a3c..abcd9513efff 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1136,7 +1136,10 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, goto out_mm; } - down_read(&mm->mmap_sem); + if (down_read_killable(&mm->mmap_sem)) { + count = -EINTR; + goto out_mm; + } tlb_gather_mmu(&tlb, mm, 0, -1); if (type == CLEAR_REFS_SOFT_DIRTY) { for (vma = mm->mmap; vma; vma = vma->vm_next) { -- 2.20.1