From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [RFC 5/8] drm/fence: add fence to drm_pending_event Date: Fri, 15 Apr 2016 21:31:33 +0200 Message-ID: <20160415193133.GA2510@phenom.ffwll.local> References: <1460683781-22535-1-git-send-email-gustavo@padovan.org> <1460683781-22535-6-git-send-email-gustavo@padovan.org> <20160415080948.GS2510@phenom.ffwll.local> <20160415185900.GD23954@joana> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-wm0-x244.google.com (mail-wm0-x244.google.com [IPv6:2a00:1450:400c:c09::244]) by gabe.freedesktop.org (Postfix) with ESMTPS id 730116ED05 for ; Fri, 15 Apr 2016 19:31:37 +0000 (UTC) Received: by mail-wm0-x244.google.com with SMTP id l6so8596527wml.3 for ; Fri, 15 Apr 2016 12:31:37 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20160415185900.GD23954@joana> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Gustavo Padovan , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Stone , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Riley Andrews , Rob Clark , Greg Hackmann , John Harrison , laurent.pinchart@ideasonboard.com, seanpaul@google.com, marcheu@google.com, m.chehab@samsung.com, Maarten Lankhorst , Gustavo Padovan List-Id: dri-devel@lists.freedesktop.org T24gRnJpLCBBcHIgMTUsIDIwMTYgYXQgMTE6NTk6MDBBTSAtMDcwMCwgR3VzdGF2byBQYWRvdmFu IHdyb3RlOgo+IDIwMTYtMDQtMTUgRGFuaWVsIFZldHRlciA8ZGFuaWVsQGZmd2xsLmNoPjoKPiA+ IE9uIFRodSwgQXByIDE0LCAyMDE2IGF0IDA2OjI5OjM4UE0gLTA3MDAsIEd1c3Rhdm8gUGFkb3Zh biB3cm90ZToKPiA+ID4gZGlmZiAtLWdpdCBhL2RyaXZlcnMvZ3B1L2RybS9kcm1fZm9wcy5jIGIv ZHJpdmVycy9ncHUvZHJtL2RybV9mb3BzLmMKPiA+ID4gaW5kZXggYWVlZjU4ZS4uMzhkZWY0OSAx MDA2NDQKPiA+ID4gLS0tIGEvZHJpdmVycy9ncHUvZHJtL2RybV9mb3BzLmMKPiA+ID4gKysrIGIv ZHJpdmVycy9ncHUvZHJtL2RybV9mb3BzLmMKPiA+ID4gQEAgLTgwMSw4ICs4MDEsOSBAQCB2b2lk IGRybV9zZW5kX2V2ZW50X2xvY2tlZChzdHJ1Y3QgZHJtX2RldmljZSAqZGV2LCBzdHJ1Y3QgZHJt X3BlbmRpbmdfZXZlbnQgKmUpCj4gPiA+ICB7Cj4gPiA+ICAJYXNzZXJ0X3NwaW5fbG9ja2VkKCZk ZXYtPmV2ZW50X2xvY2spOwo+ID4gPiAgCj4gPiA+IC0JaWYgKCFlLT5maWxlX3ByaXYpIHsKPiA+ ID4gLQkJZS0+ZGVzdHJveShlKTsKPiA+ID4gKwlpZiAoIWUtPmZpbGVfcHJpdiB8fCAhZS0+ZXZl bnQpIHsKPiA+IAo+ID4gVGhpcyB3b3VsZCBiZSBhIGJ1ZzogZS0+ZmlsZV9wcml2ICE9IE5VTEwg aWZmIGUtPmV2ZW50ICE9IE5VTEwuIEhvdyBkaWQKPiA+IHRoaXMgaGFwcGVuPwo+IAo+IE5vdCBz dXJlIG5vdy4gQnV0IEkgbmVlZGVkIHRoaXMgdG8gcHJldmVudCBhIGNyYXNoLCBJIGRvbid0IGhh dmUgbG9ncyBvZgo+IGl0IGFueW1vcmUsIEknbGwgY2hlY2sgdGhpcyBhZ2Fpbi4KClRoZXJlIHdh cyBhIG1hc3NpdmUgaXJjIGRpc2N1c3Npb24gd2l0aCBEYW5pZWwgU3RvbmUsIHNvIEknbGwgdHJ5 IHRvCnN1bW1hcml6ZSBpdCBoZXJlLiBUaGVyZSBhcmUgMyBwb3NzaWJsZSBjYXNlczoKCmUtPmZp bGVfcHJpdiA9PSBOVUxMICYmIGUtPmV2ZW50ID09IE5VTEw6ClRoaXMgaXMgYSBkcm1fZXZlbnQg d2l0aG91dCBhIGRybV9ldmVudC4gUHJvYmFibHkgZS0+ZmVuY2UgaXMgc2V0LCBpZiBub3QKdGhl biBpdCdzIGEgY29tcGxldGVsZXkgdXNlbGVzcyB0aGluZyAoYnV0IG5vdCBmb3JiaWRkZW4pLgoK ZS0+ZmlsZV9wcml2ICE9IE5VTEwgJiYgZS0+ZXZlbnQgIT0gTlVMTDoKZHJtX2V2ZW50IHdpdGgg YW4gZXZlbnQgZm9yIHRoZSBnaXZlbiBmaWxlX3ByaXYgYXR0YWNoZWQuCgplLT5maWxlX3ByaXYg PT0gTlVMTCAmJiBlLT5ldmVudCAhPSBOVUxMOgpBYm92ZSBjYXNlLCBidXQgd2l0aCB0aGUgZmls ZV9wcml2IGNsb3NlZCBhbmQgdW5saW5rZWQgZnJvbSB0aGUgZXZlbnQuCgpUaGUgNHRoIGNhc2Us IHdoaWNoIGlzIHRoZSBvbmx5IGNhc2UgdGhpbmdzIHdpbGwgY2hhbmdlIHdpdGggdGhlIGFib3Zl Cmh1bmssIGlzIG5vdCBhbGxvd2VkLiBJZiB5b3UgaGl0IGl0LCB0aGVyZSdzIGEgYnVnIHNvbWV3 aGVyZS4KClRoaXMgaXMgYWxsIGNvbXBsZXRlbHkgaWRlcGVuZGVudCBvZiBlLT5mZW5jZSwgd2hp Y2ggdGhpcyBwYXRjaCBhZGRzLgotRGFuaWVsCi0tIApEYW5pZWwgVmV0dGVyClNvZnR3YXJlIEVu Z2luZWVyLCBJbnRlbCBDb3Jwb3JhdGlvbgpodHRwOi8vYmxvZy5mZndsbC5jaApfX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpkcmktZGV2ZWwgbWFpbGluZyBs aXN0CmRyaS1kZXZlbEBsaXN0cy5mcmVlZGVza3RvcC5vcmcKaHR0cHM6Ly9saXN0cy5mcmVlZGVz a3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754057AbcDOTbl (ORCPT ); Fri, 15 Apr 2016 15:31:41 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:35720 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753185AbcDOTbh (ORCPT ); Fri, 15 Apr 2016 15:31:37 -0400 Date: Fri, 15 Apr 2016 21:31:33 +0200 From: Daniel Vetter To: Gustavo Padovan , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Stone , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Riley Andrews , Rob Clark , Greg Hackmann , John Harrison , laurent.pinchart@ideasonboard.com, seanpaul@google.com, marcheu@google.com, m.chehab@samsung.com, Maarten Lankhorst , Gustavo Padovan Subject: Re: [RFC 5/8] drm/fence: add fence to drm_pending_event Message-ID: <20160415193133.GA2510@phenom.ffwll.local> Mail-Followup-To: Gustavo Padovan , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Stone , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Riley Andrews , Rob Clark , Greg Hackmann , John Harrison , laurent.pinchart@ideasonboard.com, seanpaul@google.com, marcheu@google.com, m.chehab@samsung.com, Maarten Lankhorst , Gustavo Padovan References: <1460683781-22535-1-git-send-email-gustavo@padovan.org> <1460683781-22535-6-git-send-email-gustavo@padovan.org> <20160415080948.GS2510@phenom.ffwll.local> <20160415185900.GD23954@joana> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160415185900.GD23954@joana> X-Operating-System: Linux phenom 4.4.0-1-amd64 User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 15, 2016 at 11:59:00AM -0700, Gustavo Padovan wrote: > 2016-04-15 Daniel Vetter : > > On Thu, Apr 14, 2016 at 06:29:38PM -0700, Gustavo Padovan wrote: > > > diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c > > > index aeef58e..38def49 100644 > > > --- a/drivers/gpu/drm/drm_fops.c > > > +++ b/drivers/gpu/drm/drm_fops.c > > > @@ -801,8 +801,9 @@ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e) > > > { > > > assert_spin_locked(&dev->event_lock); > > > > > > - if (!e->file_priv) { > > > - e->destroy(e); > > > + if (!e->file_priv || !e->event) { > > > > This would be a bug: e->file_priv != NULL iff e->event != NULL. How did > > this happen? > > Not sure now. But I needed this to prevent a crash, I don't have logs of > it anymore, I'll check this again. There was a massive irc discussion with Daniel Stone, so I'll try to summarize it here. There are 3 possible cases: e->file_priv == NULL && e->event == NULL: This is a drm_event without a drm_event. Probably e->fence is set, if not then it's a completeley useless thing (but not forbidden). e->file_priv != NULL && e->event != NULL: drm_event with an event for the given file_priv attached. e->file_priv == NULL && e->event != NULL: Above case, but with the file_priv closed and unlinked from the event. The 4th case, which is the only case things will change with the above hunk, is not allowed. If you hit it, there's a bug somewhere. This is all completely idependent of e->fence, which this patch adds. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch