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 CE269C33CB1 for ; Tue, 28 Jan 2020 00:17:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F92A24681 for ; Tue, 28 Jan 2020 00:17:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580170624; bh=D2ifSG59Bc5ahx5klhoIPbIddjITgshf6qxRh3mG4R4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=196j4czjgZkuRnj5tg9b4DE1Q+Oa/gtrvH2AjCUCWGQF2whrHSETZnHivmMjGUrk1 am5y6gAIPQtRZ/QWf74Ny11yKxN2cztuomY8DShblgflv3B5kuA4CJYIT+4bTsejGx CfhP/YDNjjJ/uBLmE399lfSMDLHv6APHeWswlJ5o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727346AbgA1ARE (ORCPT ); Mon, 27 Jan 2020 19:17:04 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:35516 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727161AbgA1ARC (ORCPT ); Mon, 27 Jan 2020 19:17:02 -0500 Received: by mail-pg1-f195.google.com with SMTP id l24so6019706pgk.2; Mon, 27 Jan 2020 16:17:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7ENo+LQFzsHhuty3BkKJoKSguVUYkFockJe29Qo4mpc=; b=ocy2wX7gUdRsBNsZtjkPnol+rZ0Sop0TW/0noNZIYQe9cywJ4kuUDLVz6W/4bZa1JN Vd69qPExlyDn3MiBXaWe+VvVgp0zy3YRP7D4FGETClcNbSREVFMPWOSZs2h63TUPp5Y1 THEdG1kMsLAA4yju/MOS+H8eEnnler7ddnjDtHvOThEauG1iq44o6jm8hfoy5ws158K2 f+vxjtb++SGSDHg7XWuch2FiOImDaMMebd1nTD3TsZk96lu3uR5RXVhKyYqDrIcUsrbu uC3by1mmMITnfCvhWH8dP5yUC1YVRtCfFW9PxEPO2OVCnqIeuPlrVsE5w8dWcJAP9MQu mGjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=7ENo+LQFzsHhuty3BkKJoKSguVUYkFockJe29Qo4mpc=; b=riS+gLNCKAU4els03f4wUvauplzi386yXOl7CYdk1eE7AWAdFdtTRRUIFoWGEOLBtZ VIe60G8PwwbA5sqc/TXVUg72e0hqt3SwSV9+UmLKtQmdPwu8/ejGbMmHP2tWD8GVHAoB HtBY6bay4SwsOHLjNB1Bf6xg65TQRZYvCxcHSQMO/I1QlPrM95fPpTx+oj0P7twtBN3u SLIus5Y1jDyp5qdylTsD3rNjPyQImIKnydkxuqCxeS4eeCdbTFGxOaHU9Q3yM8W1BlVO 7qdZcafqVDtIcldNeOfw/qaqsM47luHLllQuj3qRXXDB8+AFlrpQ5HWPbFYfCzsTDJ7u OLow== X-Gm-Message-State: APjAAAUOEMEChtDCagaZQpkAdPwDxO/rocy/3M3jfMbHMOiTH8Ymiiqy S8TD7Xb8MaYsj31vAOPMssyG9DJB X-Google-Smtp-Source: APXvYqxvtzXGZuKMApqovR5A3qE1li5m7ePPP7dsGl0yzPx5L9d58S5ZdqIYJrNtvnpx/R9nRTBvHw== X-Received: by 2002:a63:2ad8:: with SMTP id q207mr22011778pgq.45.1580170621689; Mon, 27 Jan 2020 16:17:01 -0800 (PST) Received: from bbox-1.mtv.corp.google.com ([2620:15c:211:1:3e01:2939:5992:52da]) by smtp.gmail.com with ESMTPSA id q28sm11301461pfl.153.2020.01.27.16.17.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Jan 2020 16:17:00 -0800 (PST) From: Minchan Kim To: Andrew Morton Cc: LKML , linux-mm , linux-api@vger.kernel.org, oleksandr@redhat.com, Suren Baghdasaryan , Tim Murray , Daniel Colascione , Sandeep Patil , Sonny Rao , Brian Geffon , Michal Hocko , Johannes Weiner , Shakeel Butt , John Dias , Joel Fernandes , Minchan Kim Subject: [PATCH v3 3/5] mm/madvise: employ mmget_still_valid for write lock Date: Mon, 27 Jan 2020 16:16:39 -0800 Message-Id: <20200128001641.5086-4-minchan@kernel.org> X-Mailer: git-send-email 2.25.0.341.g760bfbb309-goog In-Reply-To: <20200128001641.5086-1-minchan@kernel.org> References: <20200128001641.5086-1-minchan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oleksandr Natalenko Do the very same trick as we already do since 04f5866e41fb. KSM hints will require locking mmap_sem for write since they modify vm_flags, so for remote KSM hinting this additional check is needed. Signed-off-by: Oleksandr Natalenko Signed-off-by: Minchan Kim --- mm/madvise.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/madvise.c b/mm/madvise.c index 00ffa7e92f79..bc0a72dbf80e 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1061,6 +1061,8 @@ static int madvise_common(struct task_struct *task, struct mm_struct *mm, if (write) { if (down_write_killable(&mm->mmap_sem)) return -EINTR; + if (current->mm != mm && !mmget_still_valid(mm)) + goto skip_mm; } else { down_read(&mm->mmap_sem); } @@ -1111,6 +1113,7 @@ static int madvise_common(struct task_struct *task, struct mm_struct *mm, } out: blk_finish_plug(&plug); +skip_mm: if (write) up_write(&mm->mmap_sem); else -- 2.25.0.341.g760bfbb309-goog