From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f46.google.com ([74.125.82.46]:35050 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932080AbcCQILs (ORCPT ); Thu, 17 Mar 2016 04:11:48 -0400 Received: by mail-wm0-f46.google.com with SMTP id l68so215916394wml.0 for ; Thu, 17 Mar 2016 01:11:47 -0700 (PDT) Date: Thu, 17 Mar 2016 09:12:36 +0100 From: Daniel Vetter To: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Cc: Lyude , Daniel Vetter , intel-gfx@lists.freedesktop.org, Rob Clark , stable@vger.kernel.org, "open list:INTEL DRM DRIVERS excluding Poulsbo, Moorestow..., linux-kernel@vger.kernel.org open list" Subject: Re: [PATCH] drm/i915: Fix race condition in intel_dp_destroy_mst_connector() Message-ID: <20160317081236.GC14170@phenom.ffwll.local> References: <1458155884-13877-1-git-send-email-cpaul@redhat.com> <20160316193949.GU4329@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160316193949.GU4329@intel.com> Sender: stable-owner@vger.kernel.org List-ID: On Wed, Mar 16, 2016 at 09:39:49PM +0200, Ville Syrj�l� wrote: > On Wed, Mar 16, 2016 at 03:18:04PM -0400, Lyude wrote: > > After unplugging a DP MST display from the system, we have to go through > > and destroy all of the DRM connectors associated with it since none of > > them are valid anymore. Unfortunately, intel_dp_destroy_mst_connector() > > doesn't do a good enough job of ensuring that throughout the destruction > > process that no modesettings can be done with the connectors. As it is > > right now, intel_dp_destroy_mst_connector() works like this: > > > > * Take all modeset locks > > * Clear the configuration of the crtc on the connector, if there is one > > * Drop all modeset locks, this is required because of circular > > dependency issues that arise with trying to remove the connector from > > sysfs with modeset locks held > > * Unregister the connector > > * Take all modeset locks, again > > * Do the rest of the required cleaning for destroying the connector > > * Finally drop all modeset locks for good > > So pretty much what I suspected > https://lists.freedesktop.org/archives/intel-gfx/2016-February/087734.html > > > > > This only works sometimes. During the destruction process, it's very > > possible that a userspace application will attempt to do a modesetting > > using the connector. When we drop the modeset locks, an ioctl handler > > such as drm_mode_setcrtc has the oppurtunity to take all of the modeset > > locks from us. When this happens, one thing leads to another and > > eventually we end up committing a mode with the non-existent connector: > > > > [drm:intel_dp_link_training_clock_recovery [i915]] *ERROR* failed to enable link training > > [drm:intel_dp_aux_ch] dp_aux_ch timeout status 0x7cf0001f > > [drm:intel_dp_start_link_train [i915]] *ERROR* failed to start channel equalization > > [drm:intel_dp_aux_ch] dp_aux_ch timeout status 0x7cf0001f > > [drm:intel_mst_pre_enable_dp [i915]] *ERROR* failed to allocate vcpi > > > > And in some cases, such as with the T460s using an MST dock, this > > results in breaking modesetting and/or panicking the system. > > Are these just kernel oopses etc.? If the hardware gets upset from > modesetting when the sink is gone, well, then we still have a problem > because the user can of course yank the cable while the modeset is already > underway. > > > > > To work around this, we now unregister the connector at the very > > beginning of intel_dp_destroy_mst_connector(), grab all the modesetting > > locks, and then hold them until we finish the rest of the function. > > > > CC: stable@vger.kernel.org > > Signed-off-by: Lyude > > Signed-off-by: Rob Clark > > These sobs don't make much sense to me. > > Patch itself does make sense to me, so > Reviewed-by: Ville Syrj�l� Applied, thanks. -Daniel > > > --- > > drivers/gpu/drm/i915/intel_dp_mst.c | 6 ++---- > > 1 file changed, 2 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c > > index fa0dabf..b21ac88 100644 > > --- a/drivers/gpu/drm/i915/intel_dp_mst.c > > +++ b/drivers/gpu/drm/i915/intel_dp_mst.c > > @@ -499,6 +499,8 @@ static void intel_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr, > > struct intel_connector *intel_connector = to_intel_connector(connector); > > struct drm_device *dev = connector->dev; > > > > + intel_connector->unregister(intel_connector); > > + > > /* need to nuke the connector */ > > drm_modeset_lock_all(dev); > > if (connector->state->crtc) { > > @@ -512,11 +514,7 @@ static void intel_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr, > > > > WARN(ret, "Disabling mst crtc failed with %i\n", ret); > > } > > - drm_modeset_unlock_all(dev); > > > > - intel_connector->unregister(intel_connector); > > - > > - drm_modeset_lock_all(dev); > > intel_connector_remove_from_fbdev(intel_connector); > > drm_connector_cleanup(connector); > > drm_modeset_unlock_all(dev); > > -- > > 2.5.0 > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > -- > Ville Syrj�l� > Intel OTC > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH] drm/i915: Fix race condition in intel_dp_destroy_mst_connector() Date: Thu, 17 Mar 2016 09:12:36 +0100 Message-ID: <20160317081236.GC14170@phenom.ffwll.local> References: <1458155884-13877-1-git-send-email-cpaul@redhat.com> <20160316193949.GU4329@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <20160316193949.GU4329@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Cc: Rob Clark , intel-gfx@lists.freedesktop.org, "open list:INTEL DRM DRIVERS excluding Poulsbo, Moorestow..., linux-kernel@vger.kernel.org open list" , stable@vger.kernel.org, Daniel Vetter List-Id: dri-devel@lists.freedesktop.org T24gV2VkLCBNYXIgMTYsIDIwMTYgYXQgMDk6Mzk6NDlQTSArMDIwMCwgVmlsbGUgU3lyasOkbMOk IHdyb3RlOgo+IE9uIFdlZCwgTWFyIDE2LCAyMDE2IGF0IDAzOjE4OjA0UE0gLTA0MDAsIEx5dWRl IHdyb3RlOgo+ID4gQWZ0ZXIgdW5wbHVnZ2luZyBhIERQIE1TVCBkaXNwbGF5IGZyb20gdGhlIHN5 c3RlbSwgd2UgaGF2ZSB0byBnbyB0aHJvdWdoCj4gPiBhbmQgZGVzdHJveSBhbGwgb2YgdGhlIERS TSBjb25uZWN0b3JzIGFzc29jaWF0ZWQgd2l0aCBpdCBzaW5jZSBub25lIG9mCj4gPiB0aGVtIGFy ZSB2YWxpZCBhbnltb3JlLiBVbmZvcnR1bmF0ZWx5LCBpbnRlbF9kcF9kZXN0cm95X21zdF9jb25u ZWN0b3IoKQo+ID4gZG9lc24ndCBkbyBhIGdvb2QgZW5vdWdoIGpvYiBvZiBlbnN1cmluZyB0aGF0 IHRocm91Z2hvdXQgdGhlIGRlc3RydWN0aW9uCj4gPiBwcm9jZXNzIHRoYXQgbm8gbW9kZXNldHRp bmdzIGNhbiBiZSBkb25lIHdpdGggdGhlIGNvbm5lY3RvcnMuIEFzIGl0IGlzCj4gPiByaWdodCBu b3csIGludGVsX2RwX2Rlc3Ryb3lfbXN0X2Nvbm5lY3RvcigpIHdvcmtzIGxpa2UgdGhpczoKPiA+ IAo+ID4gKiBUYWtlIGFsbCBtb2Rlc2V0IGxvY2tzCj4gPiAqIENsZWFyIHRoZSBjb25maWd1cmF0 aW9uIG9mIHRoZSBjcnRjIG9uIHRoZSBjb25uZWN0b3IsIGlmIHRoZXJlIGlzIG9uZQo+ID4gKiBE cm9wIGFsbCBtb2Rlc2V0IGxvY2tzLCB0aGlzIGlzIHJlcXVpcmVkIGJlY2F1c2Ugb2YgY2lyY3Vs YXIKPiA+ICAgZGVwZW5kZW5jeSBpc3N1ZXMgdGhhdCBhcmlzZSB3aXRoIHRyeWluZyB0byByZW1v dmUgdGhlIGNvbm5lY3RvciBmcm9tCj4gPiAgIHN5c2ZzIHdpdGggbW9kZXNldCBsb2NrcyBoZWxk Cj4gPiAqIFVucmVnaXN0ZXIgdGhlIGNvbm5lY3Rvcgo+ID4gKiBUYWtlIGFsbCBtb2Rlc2V0IGxv Y2tzLCBhZ2Fpbgo+ID4gKiBEbyB0aGUgcmVzdCBvZiB0aGUgcmVxdWlyZWQgY2xlYW5pbmcgZm9y IGRlc3Ryb3lpbmcgdGhlIGNvbm5lY3Rvcgo+ID4gKiBGaW5hbGx5IGRyb3AgYWxsIG1vZGVzZXQg bG9ja3MgZm9yIGdvb2QKPiAKPiBTbyBwcmV0dHkgbXVjaCB3aGF0IEkgc3VzcGVjdGVkCj4gaHR0 cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5vcmcvYXJjaGl2ZXMvaW50ZWwtZ2Z4LzIwMTYtRmVicnVh cnkvMDg3NzM0Lmh0bWwKPiAKPiA+IAo+ID4gVGhpcyBvbmx5IHdvcmtzIHNvbWV0aW1lcy4gRHVy aW5nIHRoZSBkZXN0cnVjdGlvbiBwcm9jZXNzLCBpdCdzIHZlcnkKPiA+IHBvc3NpYmxlIHRoYXQg YSB1c2Vyc3BhY2UgYXBwbGljYXRpb24gd2lsbCBhdHRlbXB0IHRvIGRvIGEgbW9kZXNldHRpbmcK PiA+IHVzaW5nIHRoZSBjb25uZWN0b3IuIFdoZW4gd2UgZHJvcCB0aGUgbW9kZXNldCBsb2Nrcywg YW4gaW9jdGwgaGFuZGxlcgo+ID4gc3VjaCBhcyBkcm1fbW9kZV9zZXRjcnRjIGhhcyB0aGUgb3Bw dXJ0dW5pdHkgdG8gdGFrZSBhbGwgb2YgdGhlIG1vZGVzZXQKPiA+IGxvY2tzIGZyb20gdXMuIFdo ZW4gdGhpcyBoYXBwZW5zLCBvbmUgdGhpbmcgbGVhZHMgdG8gYW5vdGhlciBhbmQKPiA+IGV2ZW50 dWFsbHkgd2UgZW5kIHVwIGNvbW1pdHRpbmcgYSBtb2RlIHdpdGggdGhlIG5vbi1leGlzdGVudCBj b25uZWN0b3I6Cj4gPiAKPiA+IAlbZHJtOmludGVsX2RwX2xpbmtfdHJhaW5pbmdfY2xvY2tfcmVj b3ZlcnkgW2k5MTVdXSAqRVJST1IqIGZhaWxlZCB0byBlbmFibGUgbGluayB0cmFpbmluZwo+ID4g CVtkcm06aW50ZWxfZHBfYXV4X2NoXSBkcF9hdXhfY2ggdGltZW91dCBzdGF0dXMgMHg3Y2YwMDAx Zgo+ID4gCVtkcm06aW50ZWxfZHBfc3RhcnRfbGlua190cmFpbiBbaTkxNV1dICpFUlJPUiogZmFp bGVkIHRvIHN0YXJ0IGNoYW5uZWwgZXF1YWxpemF0aW9uCj4gPiAJW2RybTppbnRlbF9kcF9hdXhf Y2hdIGRwX2F1eF9jaCB0aW1lb3V0IHN0YXR1cyAweDdjZjAwMDFmCj4gPiAJW2RybTppbnRlbF9t c3RfcHJlX2VuYWJsZV9kcCBbaTkxNV1dICpFUlJPUiogZmFpbGVkIHRvIGFsbG9jYXRlIHZjcGkK PiA+IAo+ID4gQW5kIGluIHNvbWUgY2FzZXMsIHN1Y2ggYXMgd2l0aCB0aGUgVDQ2MHMgdXNpbmcg YW4gTVNUIGRvY2ssIHRoaXMKPiA+IHJlc3VsdHMgaW4gYnJlYWtpbmcgbW9kZXNldHRpbmcgYW5k L29yIHBhbmlja2luZyB0aGUgc3lzdGVtLgo+IAo+IEFyZSB0aGVzZSBqdXN0IGtlcm5lbCBvb3Bz ZXMgZXRjLj8gSWYgdGhlIGhhcmR3YXJlIGdldHMgdXBzZXQgZnJvbQo+IG1vZGVzZXR0aW5nIHdo ZW4gdGhlIHNpbmsgaXMgZ29uZSwgd2VsbCwgdGhlbiB3ZSBzdGlsbCBoYXZlIGEgcHJvYmxlbQo+ IGJlY2F1c2UgdGhlIHVzZXIgY2FuIG9mIGNvdXJzZSB5YW5rIHRoZSBjYWJsZSB3aGlsZSB0aGUg bW9kZXNldCBpcyBhbHJlYWR5Cj4gdW5kZXJ3YXkuCj4gCj4gPiAKPiA+IFRvIHdvcmsgYXJvdW5k IHRoaXMsIHdlIG5vdyB1bnJlZ2lzdGVyIHRoZSBjb25uZWN0b3IgYXQgdGhlIHZlcnkKPiA+IGJl Z2lubmluZyBvZiBpbnRlbF9kcF9kZXN0cm95X21zdF9jb25uZWN0b3IoKSwgZ3JhYiBhbGwgdGhl IG1vZGVzZXR0aW5nCj4gPiBsb2NrcywgYW5kIHRoZW4gaG9sZCB0aGVtIHVudGlsIHdlIGZpbmlz aCB0aGUgcmVzdCBvZiB0aGUgZnVuY3Rpb24uCj4gPiAKPiA+IENDOiBzdGFibGVAdmdlci5rZXJu ZWwub3JnCj4gPiBTaWduZWQtb2ZmLWJ5OiBMeXVkZSA8Y3BhdWxAcmVkaGF0LmNvbT4KPiA+IFNp Z25lZC1vZmYtYnk6IFJvYiBDbGFyayA8cmNsYXJrQHJlZGhhdC5jb20+Cj4gCj4gVGhlc2Ugc29i cyBkb24ndCBtYWtlIG11Y2ggc2Vuc2UgdG8gbWUuCj4gCj4gUGF0Y2ggaXRzZWxmIGRvZXMgbWFr ZSBzZW5zZSB0byBtZSwgc28gCj4gUmV2aWV3ZWQtYnk6IFZpbGxlIFN5cmrDpGzDpCA8dmlsbGUu c3lyamFsYUBsaW51eC5pbnRlbC5jb20+CgpBcHBsaWVkLCB0aGFua3MuCi1EYW5pZWwKCj4gCj4g PiAtLS0KPiA+ICBkcml2ZXJzL2dwdS9kcm0vaTkxNS9pbnRlbF9kcF9tc3QuYyB8IDYgKystLS0t Cj4gPiAgMSBmaWxlIGNoYW5nZWQsIDIgaW5zZXJ0aW9ucygrKSwgNCBkZWxldGlvbnMoLSkKPiA+ IAo+ID4gZGlmZiAtLWdpdCBhL2RyaXZlcnMvZ3B1L2RybS9pOTE1L2ludGVsX2RwX21zdC5jIGIv ZHJpdmVycy9ncHUvZHJtL2k5MTUvaW50ZWxfZHBfbXN0LmMKPiA+IGluZGV4IGZhMGRhYmYuLmIy MWFjODggMTAwNjQ0Cj4gPiAtLS0gYS9kcml2ZXJzL2dwdS9kcm0vaTkxNS9pbnRlbF9kcF9tc3Qu Ywo+ID4gKysrIGIvZHJpdmVycy9ncHUvZHJtL2k5MTUvaW50ZWxfZHBfbXN0LmMKPiA+IEBAIC00 OTksNiArNDk5LDggQEAgc3RhdGljIHZvaWQgaW50ZWxfZHBfZGVzdHJveV9tc3RfY29ubmVjdG9y KHN0cnVjdCBkcm1fZHBfbXN0X3RvcG9sb2d5X21nciAqbWdyLAo+ID4gIAlzdHJ1Y3QgaW50ZWxf Y29ubmVjdG9yICppbnRlbF9jb25uZWN0b3IgPSB0b19pbnRlbF9jb25uZWN0b3IoY29ubmVjdG9y KTsKPiA+ICAJc3RydWN0IGRybV9kZXZpY2UgKmRldiA9IGNvbm5lY3Rvci0+ZGV2Owo+ID4gIAo+ ID4gKwlpbnRlbF9jb25uZWN0b3ItPnVucmVnaXN0ZXIoaW50ZWxfY29ubmVjdG9yKTsKPiA+ICsK PiA+ICAJLyogbmVlZCB0byBudWtlIHRoZSBjb25uZWN0b3IgKi8KPiA+ICAJZHJtX21vZGVzZXRf bG9ja19hbGwoZGV2KTsKPiA+ICAJaWYgKGNvbm5lY3Rvci0+c3RhdGUtPmNydGMpIHsKPiA+IEBA IC01MTIsMTEgKzUxNCw3IEBAIHN0YXRpYyB2b2lkIGludGVsX2RwX2Rlc3Ryb3lfbXN0X2Nvbm5l Y3RvcihzdHJ1Y3QgZHJtX2RwX21zdF90b3BvbG9neV9tZ3IgKm1nciwKPiA+ICAKPiA+ICAJCVdB Uk4ocmV0LCAiRGlzYWJsaW5nIG1zdCBjcnRjIGZhaWxlZCB3aXRoICVpXG4iLCByZXQpOwo+ID4g IAl9Cj4gPiAtCWRybV9tb2Rlc2V0X3VubG9ja19hbGwoZGV2KTsKPiA+ICAKPiA+IC0JaW50ZWxf Y29ubmVjdG9yLT51bnJlZ2lzdGVyKGludGVsX2Nvbm5lY3Rvcik7Cj4gPiAtCj4gPiAtCWRybV9t b2Rlc2V0X2xvY2tfYWxsKGRldik7Cj4gPiAgCWludGVsX2Nvbm5lY3Rvcl9yZW1vdmVfZnJvbV9m YmRldihpbnRlbF9jb25uZWN0b3IpOwo+ID4gIAlkcm1fY29ubmVjdG9yX2NsZWFudXAoY29ubmVj dG9yKTsKPiA+ICAJZHJtX21vZGVzZXRfdW5sb2NrX2FsbChkZXYpOwo+ID4gLS0gCj4gPiAyLjUu MAo+ID4gCj4gPiBfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f Xwo+ID4gZHJpLWRldmVsIG1haWxpbmcgbGlzdAo+ID4gZHJpLWRldmVsQGxpc3RzLmZyZWVkZXNr dG9wLm9yZwo+ID4gaHR0cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5m by9kcmktZGV2ZWwKPiAKPiAtLSAKPiBWaWxsZSBTeXJqw6Rsw6QKPiBJbnRlbCBPVEMKPiBfX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwo+IGRyaS1kZXZlbCBt YWlsaW5nIGxpc3QKPiBkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCj4gaHR0cHM6Ly9s aXN0cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwKCi0tIApEYW5p ZWwgVmV0dGVyClNvZnR3YXJlIEVuZ2luZWVyLCBJbnRlbCBDb3Jwb3JhdGlvbgpodHRwOi8vYmxv Zy5mZndsbC5jaApfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f XwpJbnRlbC1nZnggbWFpbGluZyBsaXN0CkludGVsLWdmeEBsaXN0cy5mcmVlZGVza3RvcC5vcmcK aHR0cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9pbnRlbC1nZngK