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=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 44A5FC433E0 for ; Thu, 23 Jul 2020 17:48:51 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 32267207BB for ; Thu, 23 Jul 2020 17:48:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 32267207BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BB47A6E191; Thu, 23 Jul 2020 17:48:49 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0BCD06E191; Thu, 23 Jul 2020 17:48:46 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 21910932-1500050 for multiple; Thu, 23 Jul 2020 18:48:44 +0100 MIME-Version: 1.0 In-Reply-To: <1D440B9B88E22A4ABEF89F9F1F81BC290117BC5431@ORSMSX163.amr.corp.intel.com> References: <20200723172119.17649-1-chris@chris-wilson.co.uk> <20200723172119.17649-2-chris@chris-wilson.co.uk> <1D440B9B88E22A4ABEF89F9F1F81BC290117BC5431@ORSMSX163.amr.corp.intel.com> From: Chris Wilson To: "Tang, CQ" , intel-gfx@lists.freedesktop.org Date: Thu, 23 Jul 2020 18:48:42 +0100 Message-ID: <159552652244.21069.17962945806364093006@build.alporthouse.com> User-Agent: alot/0.9 Subject: Re: [Intel-gfx] [PATCH 2/3] drm/i915/gem: Move context decoupling from postclose to preclose 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: , Cc: "Vetter, Daniel" , dri-devel@lists.freedesktop.org, stable@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Quoting Tang, CQ (2020-07-23 18:44:08) > > > > -----Original Message----- > > From: Chris Wilson > > Sent: Thursday, July 23, 2020 10:21 AM > > To: intel-gfx@lists.freedesktop.org > > Cc: dri-devel@lists.freedesktop.org; Chris Wilson ; > > Tang, CQ ; Vetter, Daniel ; > > stable@vger.kernel.org > > Subject: [PATCH 2/3] drm/i915/gem: Move context decoupling from > > postclose to preclose > > > > Since the GEM contexts refer to other GEM state, we need to nerf those > > pointers before that state is freed during drm_gem_release(). We need to > > move i915_gem_context_close() from the postclose callback to the preclose. > > > > In particular, debugfs likes to peek into the GEM contexts, and from there > > peek at the drm core objects. If the context is closed during the peeking, we > > may attempt to dereference a stale core object. > > > > Signed-off-by: Chris Wilson > > Cc: CQ Tang > > Cc: Daniel Vetter > > Cc: stable@vger.kernel.org > > --- > > drivers/gpu/drm/i915/i915_drv.c | 7 ++++++- > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.c > > b/drivers/gpu/drm/i915/i915_drv.c index 5fd5af4bc855..15242a8c70f7 100644 > > --- a/drivers/gpu/drm/i915/i915_drv.c > > +++ b/drivers/gpu/drm/i915/i915_drv.c > > @@ -1114,11 +1114,15 @@ static void i915_driver_lastclose(struct > > drm_device *dev) > > vga_switcheroo_process_delayed_switch(); > > } > > > > +static void i915_driver_preclose(struct drm_device *dev, struct > > +drm_file *file) { > > + i915_gem_context_close(file); > > +} > > + > > static void i915_driver_postclose(struct drm_device *dev, struct drm_file > > *file) { > > struct drm_i915_file_private *file_priv = file->driver_priv; > > > > - i915_gem_context_close(file); > > i915_gem_release(dev, file); > > Now we separate i915_gem_context_close() from i915_gem_release() and other freeing code in postclose(), is there any side effect to allow code to run in between? > Can we move all postclose() code into preclose()? i915_gem_release() is scheduled for deletion, so I didn't care. What remains in postclose are the kfree + tidyup, which seem like a good idea to keep last. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx