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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 C8E96C31E49 for ; Sun, 16 Jun 2019 08:58:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A477721473 for ; Sun, 16 Jun 2019 08:58:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727195AbfFPI6s (ORCPT ); Sun, 16 Jun 2019 04:58:48 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:39923 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727167AbfFPI6p (ORCPT ); Sun, 16 Jun 2019 04:58:45 -0400 Received: by mail-wr1-f66.google.com with SMTP id x4so6675540wrt.6 for ; Sun, 16 Jun 2019 01:58:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=BH7q4sQxtlW7GBy0Ndsur0wfVLJQqa1DwxMiAYKl/M8=; b=aAjaburQSWC+9Dn9WNbPZvncTX//ni6q6saNVCajfpRhwJ+mqmMtex8zBnivIYFZIt +JPJwYN5gzFrUsembuU2eNvTUuIgy1L+tdUkqQ5XiABzLOeKDJzNo1nq6p7cy2RXu2/X A6e7DMKmdlj5ykZ9ZKdFAUlKMLuW6WnNiBRdNFjuI8XQ0s/hVZdiB58r0rftimggjSPW 3Qph4M5pwvIwAOtqlBNDEf65FzyuJBp0S4taIZ3YyKkX3YaDJaAis/WS41SJkNw8OLJt jXgWOr59I2JCr3rtKIfLEWpBFFqArG7lO3QNC30yqVRhcpTDvIn3ksFoI5T530FBBDtw 3cyg== X-Gm-Message-State: APjAAAX0CdOmJUjijQVRzzijTy4yEdsNkMxvlTU/w768us+QTO7+6hUh AFa2ZPTZazDuxCwKXx8Vm1Ju5w== X-Google-Smtp-Source: APXvYqz8xNHGO6SpiHfeRXmpPOlMaBmRTs2Z+ZnB2utwNn6Sw4tv3GLfcp5kGY1tE4/gW0/NkQufFQ== X-Received: by 2002:a5d:5702:: with SMTP id a2mr28113288wrv.89.1560675523661; Sun, 16 Jun 2019 01:58:43 -0700 (PDT) Received: from localhost (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id e7sm6195627wmd.0.2019.06.16.01.58.42 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Sun, 16 Jun 2019 01:58:43 -0700 (PDT) From: Oleksandr Natalenko To: Minchan Kim Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org Subject: [PATCH NOTFORMERGE 4/5] mm/madvise: employ mmget_still_valid for write lock Date: Sun, 16 Jun 2019 10:58:34 +0200 Message-Id: <20190616085835.953-5-oleksandr@redhat.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190616085835.953-1-oleksandr@redhat.com> References: <20190616085835.953-1-oleksandr@redhat.com> 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 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 --- mm/madvise.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/madvise.c b/mm/madvise.c index 9755340da157..84f899b1b6da 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1049,6 +1049,8 @@ 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); } @@ -1099,6 +1101,7 @@ 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 -- 2.22.0