From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: Re: [PATCH v1 1/5] drivercore: Revert "deferral race condition fix" Date: Sat, 10 Nov 2018 10:26:22 -0800 Message-ID: <20181110182622.GA32657@kroah.com> References: <20181110181101.24557-1-andriy.shevchenko@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181110181101.24557-1-andriy.shevchenko@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Andy Shevchenko Cc: MyungJoo Ham , Chanwoo Choi , linux-usb@vger.kernel.org, Felipe Balbi , Guenter Roeck , Heikki Krogerus , Roger Quadros , linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Sebastian Reichel , linux-omap@vger.kernel.org, Darren Hart , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Chen-Yu Tsai , Hans de Goede , Grant Likely , Peter Ujfalusi , Mark Brown , Andrzej Hajda List-Id: linux-omap@vger.kernel.org On Sat, Nov 10, 2018 at 08:10:57PM +0200, Andy Shevchenko wrote: > Consider the following scenario. > > There are two independent devices coupled together by functional dependencies: > - USB OTG (dwc3-pci) > - extcon (tested with extcon-intel-mrfld, not yet in upstream) > > Each of the driver services a corresponding device is built as a module. In the > Buildroot environment the modules are probed by alphabetical ordering of their > modaliases. The latter comes to the case when USB OTG driver will be probed > first followed by extcon one. > > So, if the platform anticipates extcon device to be appeared, in the above case > we will get deferred probe of USB OTG, because of ordering. > > Now, a cherry on top of the cake, the deferred probing list contains > the only two modules, i.e. USB OTG and extcon. Due to above circumstances, > values in the local_trigger_count and deferred_trigger_count are not the same, > and thus provokes deferred probe triggering again and again. > > ... > [ 20.678332] platform dwc3.0.auto: Retrying from deferred list > [ 20.694743] platform dwc3.0.auto: Driver dwc3 requests probe deferral > [ 20.701254] platform dwc3.0.auto: Added to deferred list > [ 20.706620] platform dwc3.0.auto: driver_deferred_probe_add_trigger 1 2 > [ 20.713732] platform dwc3.0.auto: Retrying from deferred list > [ 20.730035] platform dwc3.0.auto: Driver dwc3 requests probe deferral > [ 20.736540] platform dwc3.0.auto: Added to deferred list > [ 20.741889] platform dwc3.0.auto: driver_deferred_probe_add_trigger 3 4 > [ 20.748991] platform dwc3.0.auto: Retrying from deferred list > [ 20.765416] platform dwc3.0.auto: Driver dwc3 requests probe deferral > [ 20.771914] platform dwc3.0.auto: Added to deferred list > [ 20.777279] platform dwc3.0.auto: driver_deferred_probe_add_trigger 5 6 > ... > > Deeper investigation shows the culprit commit 58b116bce136 > ("drivercore: deferral race condition fix") which was dedicated to fix some > other issue while bringing a regression. > > This reverts commit 58b116bce13612e5aa6fcd49ecbd4cf8bb59e835 for good until > we will have better solution. > > Cc: Grant Likely > Cc: Peter Ujfalusi > Cc: Greg Kroah-Hartman > Cc: Mark Brown > Cc: Felipe Balbi > Cc: Andrzej Hajda > Signed-off-by: Andy Shevchenko > --- > drivers/base/dd.c | 27 ++------------------------- > 1 file changed, 2 insertions(+), 25 deletions(-) Shouldn't there be a "Fixes:" line and cc: stable here? thanks, greg k-h From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v1,1/5] drivercore: Revert "deferral race condition fix" From: Greg Kroah-Hartman Message-Id: <20181110182622.GA32657@kroah.com> Date: Sat, 10 Nov 2018 10:26:22 -0800 To: Andy Shevchenko Cc: MyungJoo Ham , Chanwoo Choi , linux-usb@vger.kernel.org, Felipe Balbi , Guenter Roeck , Heikki Krogerus , Roger Quadros , linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Sebastian Reichel , linux-omap@vger.kernel.org, Darren Hart , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Chen-Yu Tsai , Hans de Goede , Grant Likely , Peter Ujfalusi , Mark Brown , Andrzej Hajda List-ID: T24gU2F0LCBOb3YgMTAsIDIwMTggYXQgMDg6MTA6NTdQTSArMDIwMCwgQW5keSBTaGV2Y2hlbmtv IHdyb3RlOgo+IENvbnNpZGVyIHRoZSBmb2xsb3dpbmcgc2NlbmFyaW8uCj4gCj4gVGhlcmUgYXJl IHR3byBpbmRlcGVuZGVudCBkZXZpY2VzIGNvdXBsZWQgdG9nZXRoZXIgYnkgZnVuY3Rpb25hbCBk ZXBlbmRlbmNpZXM6Cj4gIC0gVVNCIE9URyAoZHdjMy1wY2kpCj4gIC0gZXh0Y29uICh0ZXN0ZWQg d2l0aCBleHRjb24taW50ZWwtbXJmbGQsIG5vdCB5ZXQgaW4gdXBzdHJlYW0pCj4gCj4gRWFjaCBv ZiB0aGUgZHJpdmVyIHNlcnZpY2VzIGEgY29ycmVzcG9uZGluZyBkZXZpY2UgaXMgYnVpbHQgYXMg YSBtb2R1bGUuIEluIHRoZQo+IEJ1aWxkcm9vdCBlbnZpcm9ubWVudCB0aGUgbW9kdWxlcyBhcmUg cHJvYmVkIGJ5IGFscGhhYmV0aWNhbCBvcmRlcmluZyBvZiB0aGVpcgo+IG1vZGFsaWFzZXMuIFRo ZSBsYXR0ZXIgY29tZXMgdG8gdGhlIGNhc2Ugd2hlbiBVU0IgT1RHIGRyaXZlciB3aWxsIGJlIHBy b2JlZAo+IGZpcnN0IGZvbGxvd2VkIGJ5IGV4dGNvbiBvbmUuCj4gCj4gU28sIGlmIHRoZSBwbGF0 Zm9ybSBhbnRpY2lwYXRlcyBleHRjb24gZGV2aWNlIHRvIGJlIGFwcGVhcmVkLCBpbiB0aGUgYWJv dmUgY2FzZQo+IHdlIHdpbGwgZ2V0IGRlZmVycmVkIHByb2JlIG9mIFVTQiBPVEcsIGJlY2F1c2Ug b2Ygb3JkZXJpbmcuCj4gCj4gTm93LCBhIGNoZXJyeSBvbiB0b3Agb2YgdGhlIGNha2UsIHRoZSBk ZWZlcnJlZCBwcm9iaW5nIGxpc3QgY29udGFpbnMKPiB0aGUgb25seSB0d28gbW9kdWxlcywgaS5l LiBVU0IgT1RHIGFuZCBleHRjb24uIER1ZSB0byBhYm92ZSBjaXJjdW1zdGFuY2VzLAo+IHZhbHVl cyBpbiB0aGUgbG9jYWxfdHJpZ2dlcl9jb3VudCBhbmQgZGVmZXJyZWRfdHJpZ2dlcl9jb3VudCBh cmUgbm90IHRoZSBzYW1lLAo+IGFuZCB0aHVzIHByb3Zva2VzIGRlZmVycmVkIHByb2JlIHRyaWdn ZXJpbmcgYWdhaW4gYW5kIGFnYWluLgo+IAo+IC4uLgo+IFsgICAyMC42NzgzMzJdIHBsYXRmb3Jt IGR3YzMuMC5hdXRvOiBSZXRyeWluZyBmcm9tIGRlZmVycmVkIGxpc3QKPiBbICAgMjAuNjk0NzQz XSBwbGF0Zm9ybSBkd2MzLjAuYXV0bzogRHJpdmVyIGR3YzMgcmVxdWVzdHMgcHJvYmUgZGVmZXJy YWwKPiBbICAgMjAuNzAxMjU0XSBwbGF0Zm9ybSBkd2MzLjAuYXV0bzogQWRkZWQgdG8gZGVmZXJy ZWQgbGlzdAo+IFsgICAyMC43MDY2MjBdIHBsYXRmb3JtIGR3YzMuMC5hdXRvOiBkcml2ZXJfZGVm ZXJyZWRfcHJvYmVfYWRkX3RyaWdnZXIgMSAyCj4gWyAgIDIwLjcxMzczMl0gcGxhdGZvcm0gZHdj My4wLmF1dG86IFJldHJ5aW5nIGZyb20gZGVmZXJyZWQgbGlzdAo+IFsgICAyMC43MzAwMzVdIHBs YXRmb3JtIGR3YzMuMC5hdXRvOiBEcml2ZXIgZHdjMyByZXF1ZXN0cyBwcm9iZSBkZWZlcnJhbAo+ IFsgICAyMC43MzY1NDBdIHBsYXRmb3JtIGR3YzMuMC5hdXRvOiBBZGRlZCB0byBkZWZlcnJlZCBs aXN0Cj4gWyAgIDIwLjc0MTg4OV0gcGxhdGZvcm0gZHdjMy4wLmF1dG86IGRyaXZlcl9kZWZlcnJl ZF9wcm9iZV9hZGRfdHJpZ2dlciAzIDQKPiBbICAgMjAuNzQ4OTkxXSBwbGF0Zm9ybSBkd2MzLjAu YXV0bzogUmV0cnlpbmcgZnJvbSBkZWZlcnJlZCBsaXN0Cj4gWyAgIDIwLjc2NTQxNl0gcGxhdGZv cm0gZHdjMy4wLmF1dG86IERyaXZlciBkd2MzIHJlcXVlc3RzIHByb2JlIGRlZmVycmFsCj4gWyAg IDIwLjc3MTkxNF0gcGxhdGZvcm0gZHdjMy4wLmF1dG86IEFkZGVkIHRvIGRlZmVycmVkIGxpc3QK PiBbICAgMjAuNzc3Mjc5XSBwbGF0Zm9ybSBkd2MzLjAuYXV0bzogZHJpdmVyX2RlZmVycmVkX3By b2JlX2FkZF90cmlnZ2VyIDUgNgo+IC4uLgo+IAo+IERlZXBlciBpbnZlc3RpZ2F0aW9uIHNob3dz IHRoZSBjdWxwcml0IGNvbW1pdCA1OGIxMTZiY2UxMzYKPiAoImRyaXZlcmNvcmU6IGRlZmVycmFs IHJhY2UgY29uZGl0aW9uIGZpeCIpIHdoaWNoIHdhcyBkZWRpY2F0ZWQgdG8gZml4IHNvbWUKPiBv dGhlciBpc3N1ZSB3aGlsZSBicmluZ2luZyBhIHJlZ3Jlc3Npb24uCj4gCj4gVGhpcyByZXZlcnRz IGNvbW1pdCA1OGIxMTZiY2UxMzYxMmU1YWE2ZmNkNDllY2JkNGNmOGJiNTllODM1IGZvciBnb29k IHVudGlsCj4gd2Ugd2lsbCBoYXZlIGJldHRlciBzb2x1dGlvbi4KPiAKPiBDYzogR3JhbnQgTGlr ZWx5IDxncmFudC5saWtlbHlAbGluYXJvLm9yZz4KPiBDYzogUGV0ZXIgVWpmYWx1c2kgPHBldGVy LnVqZmFsdXNpQHRpLmNvbT4KPiBDYzogR3JlZyBLcm9haC1IYXJ0bWFuIDxncmVna2hAbGludXhm b3VuZGF0aW9uLm9yZz4KPiBDYzogTWFyayBCcm93biA8YnJvb25pZUBrZXJuZWwub3JnPgo+IENj OiBGZWxpcGUgQmFsYmkgPGJhbGJpQGtlcm5lbC5vcmc+Cj4gQ2M6IEFuZHJ6ZWogSGFqZGEgPGEu aGFqZGFAc2Ftc3VuZy5jb20+Cj4gU2lnbmVkLW9mZi1ieTogQW5keSBTaGV2Y2hlbmtvIDxhbmRy aXkuc2hldmNoZW5rb0BsaW51eC5pbnRlbC5jb20+Cj4gLS0tCj4gIGRyaXZlcnMvYmFzZS9kZC5j IHwgMjcgKystLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tCj4gIDEgZmlsZSBjaGFuZ2VkLCAyIGlu c2VydGlvbnMoKyksIDI1IGRlbGV0aW9ucygtKQoKU2hvdWxkbid0IHRoZXJlIGJlIGEgIkZpeGVz OiIgbGluZSBhbmQgY2M6IHN0YWJsZSBoZXJlPwoKdGhhbmtzLAoKZ3JlZyBrLWgK