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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E6CBC433EF for ; Mon, 15 Nov 2021 20:53:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 183A961AAA for ; Mon, 15 Nov 2021 20:53:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232633AbhKOU4i (ORCPT ); Mon, 15 Nov 2021 15:56:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:50066 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240636AbhKOSLd (ORCPT ); Mon, 15 Nov 2021 13:11:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C2EF6633C0; Mon, 15 Nov 2021 17:47:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636998443; bh=WNfqfHL+XDuPIiFCSXiN5p1SQMFshojtqrcyDtt4W3A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KaPibCM9ypVaIY1uMetN8P2fV1VvTfxZ5wbhBp5kMg2rcn5L0dpULQn/HT1FuY3dp 5JlZA55FTHO4Ax0+BFoGcPKW7lRsKur+tNN/Fx5H6onx8/C4kGhvf3RjykDZ1kJxkg 3jZNW2c0bMsCLFsVYJ8YRQ4AX9yFbIBK39ABQjTU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chenyuan Mi , Xiyu Yang , Xin Tan , Lyude Paul , Ben Skeggs , Karol Herbst , Sasha Levin Subject: [PATCH 5.10 512/575] drm/nouveau/svm: Fix refcount leak bug and missing check against null bug Date: Mon, 15 Nov 2021 18:03:57 +0100 Message-Id: <20211115165401.391650995@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165343.579890274@linuxfoundation.org> References: <20211115165343.579890274@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chenyuan Mi [ Upstream commit 6bb8c2d51811eb5e6504f49efe3b089d026009d2 ] The reference counting issue happens in one exception handling path of nouveau_svmm_bind(). When cli->svm.svmm is null, the function forgets to decrease the refcount of mm increased by get_task_mm(), causing a refcount leak. Fix this issue by using mmput() to decrease the refcount in the exception handling path. Also, the function forgets to do check against null when get mm by get_task_mm(). Fix this issue by adding null check after get mm by get_task_mm(). Signed-off-by: Chenyuan Mi Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Fixes: 822cab6150d3 ("drm/nouveau/svm: check for SVM initialized before migrating") Reviewed-by: Lyude Paul Reviewed-by: Ben Skeggs Reviewed-by: Karol Herbst Signed-off-by: Karol Herbst Link: https://patchwork.freedesktop.org/patch/msgid/20210907122633.16665-1-cymi20@fudan.edu.cn Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/14 Signed-off-by: Sasha Levin --- drivers/gpu/drm/nouveau/nouveau_svm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c index 1c3f890377d2c..f67700c028c75 100644 --- a/drivers/gpu/drm/nouveau/nouveau_svm.c +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c @@ -156,10 +156,14 @@ nouveau_svmm_bind(struct drm_device *dev, void *data, */ mm = get_task_mm(current); + if (!mm) { + return -EINVAL; + } mmap_read_lock(mm); if (!cli->svm.svmm) { mmap_read_unlock(mm); + mmput(mm); return -EINVAL; } -- 2.33.0