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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5FA93C48BC3 for ; Tue, 20 Feb 2024 09:05:38 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 44C2910E241; Tue, 20 Feb 2024 09:05:36 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="PLzNP2xl"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6E85010E228; Tue, 20 Feb 2024 09:05:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708419934; x=1739955934; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to; bh=rK9FL6IDYVMVqTKSg8C6FYwyy3TTQyNND9BPOP/bnN4=; b=PLzNP2xlkFQW0po31KuY5yasjiPSRBE3WR8NdNFY3z3cNAu/PwDe71lR KUuGrfw4euKiM/28nvnk2I4Or/8Ms0vDO+CZsrwjho8+DvUNKVjfSb7rd yxxEjfPX6M0dCj4nvaCW3xXy+wvpK3uFtbhE3P4jLa2d9kCt5QoVuzx7T WzlXzK1WE+BkYbV5n4UavJO/JZXJpk/PKRzKiBYtKbP8cImsZY/G1mdKv RNv4UYxXK2/2y0aNQSm29wVwgri4ex6Xt+OoAtcA8JH5GoAH4dg3ydg8d 4jxsK5j3aG3ZE2NKffANeww8y54F45ft89DnQEMxzNpIDBIj8JPQz6cVO g==; X-IronPort-AV: E=McAfee;i="6600,9927,10989"; a="6328628" X-IronPort-AV: E=Sophos;i="6.06,172,1705392000"; d="scan'208,217";a="6328628" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Feb 2024 01:05:33 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,172,1705392000"; d="scan'208,217";a="9419269" Received: from nirmoyda-mobl.ger.corp.intel.com (HELO [10.246.50.249]) ([10.246.50.249]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Feb 2024 01:05:31 -0800 Content-Type: multipart/alternative; boundary="------------10jooFcKQFnxlMRDcWq7DseM" Message-ID: <97d6c6a4-dd1c-44af-a670-4867b6ae3cab@linux.intel.com> Date: Tue, 20 Feb 2024 10:05:29 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/i915: check before removing mm notifier To: Rodrigo Vivi , Nirmoy Das Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Andi Shyti , Shawn Lee References: <20240219125047.28906-1-nirmoy.das@intel.com> Content-Language: en-US From: Nirmoy Das In-Reply-To: X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" This is a multi-part message in MIME format. --------------10jooFcKQFnxlMRDcWq7DseM Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Rodrigo, On 2/19/2024 9:12 PM, Rodrigo Vivi wrote: > On Mon, Feb 19, 2024 at 01:50:47PM +0100, Nirmoy Das wrote: >> Error in mmu_interval_notifier_insert() can leave a NULL >> notifier.mm pointer. Catch that and return early. >> >> Cc: Andi Shyti >> Cc: Shawn Lee >> Signed-off-by: Nirmoy Das >> --- >> drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c >> index 0e21ce9d3e5a..61abfb505766 100644 >> --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c >> +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c >> @@ -349,6 +349,9 @@ i915_gem_userptr_release(struct drm_i915_gem_object *obj) >> { >> GEM_WARN_ON(obj->userptr.page_ref); >> >> + if (!obj->userptr.notifier.mm) >> + return; >> + > hmmm... right, it looks that we need this protection. But... > > I mean, feel free to use > Reviewed-by: Rodrigo Vivi > > for this patch, > > but I believe that if this mmu insert failed we might have other > deeper problems like when checking i915_gem_object_is_userptr() ? > > No?! We are returning an error if mmu insert fails while creating a userptr object  so the obj struct is only available to obj cleanup methods. As far as I see, i915_gem_object_is_userptr() should not happen on such obj struct. Thanks, Nirmoy >> mmu_interval_notifier_remove(&obj->userptr.notifier); >> obj->userptr.notifier.mm = NULL; >> } >> -- >> 2.42.0 >> --------------10jooFcKQFnxlMRDcWq7DseM Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit

Hi Rodrigo,

On 2/19/2024 9:12 PM, Rodrigo Vivi wrote:
On Mon, Feb 19, 2024 at 01:50:47PM +0100, Nirmoy Das wrote:

Error in mmu_interval_notifier_insert() can leave a NULL
notifier.mm pointer. Catch that and return early.

Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Shawn Lee <shawn.c.lee@intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 0e21ce9d3e5a..61abfb505766 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -349,6 +349,9 @@ i915_gem_userptr_release(struct drm_i915_gem_object *obj)
 {
 	GEM_WARN_ON(obj->userptr.page_ref);
 
+	if (!obj->userptr.notifier.mm)
+		return;
+

hmmm... right, it looks that we need this protection. But...

I mean, feel free to use
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

for this patch,

but I believe that if this mmu insert failed we might have other
deeper problems like when checking i915_gem_object_is_userptr() ?

No?!

We are returning an error if mmu insert fails while creating a userptr object  so the obj struct is only available to obj cleanup methods.

As far as I see, i915_gem_object_is_userptr() should not happen on such obj struct.

Thanks,
Nirmoy 

 	mmu_interval_notifier_remove(&obj->userptr.notifier);
 	obj->userptr.notifier.mm = NULL;
 }
-- 
2.42.0
--------------10jooFcKQFnxlMRDcWq7DseM--