From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from v-smtpgw2.han.skanova.net ([81.236.60.205]:53667 "EHLO v-smtpgw2.han.skanova.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727780AbeKNWVt (ORCPT ); Wed, 14 Nov 2018 17:21:49 -0500 Subject: Re: [PATCH] media: rc: cec devices do not have a lirc chardev To: Sean Young , Hans Verkuil Cc: Linux Media Mailing List , stable@vger.kernel.org References: <20181022085910.2gndxc75zcqkto5z@gofer.mess.org> <1a63a5b5-644f-cef4-d0ad-9ae3bf491f9a@mbox200.swipnet.se> <20181022101405.v7setqacuftrafrb@gofer.mess.org> <45261f15-b022-8871-b087-937988b3bf1f@xs4all.nl> <20181022122842.mvrvpfyaflvmtbf6@gofer.mess.org> <20181022131727.yf5e6gorccs3m6w7@gofer.mess.org> From: Torbjorn Jansson Message-ID: Date: Wed, 14 Nov 2018 13:18:47 +0100 MIME-Version: 1.0 In-Reply-To: <20181022131727.yf5e6gorccs3m6w7@gofer.mess.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 2018-10-22 15:17, Sean Young wrote: > On Mon, Oct 22, 2018 at 01:28:42PM +0100, Sean Young wrote: >> On Mon, Oct 22, 2018 at 12:30:29PM +0100, Hans Verkuil wrote: >>> On 10/22/2018 11:14 AM, Sean Young wrote: >>>> Would you be able to test the following patch please? >>> >>> Sean, >>> >>> I think you should be able to test this with the vivid driver. Load the vivid driver, >>> run: >>> >>> cec-ctl --tv; cec-ctl -d1 --playback >>> >>> Then: >>> >>> cec-ctl -d1 -t0 --user-control-pressed ui-cmd=F5 >> >> Ah, thanks. That will help with testing/reproducing. >> >>> That said, I tried this, but it doesn't crash for me, but perhaps I need to run >>> some RC command first... >> >> Hmm I think those commands should be enough. It probably needs >> CONFIG_DEBUG_SPINLOCK to detect the uninitialized spinlock. I'm trying it now. > > Yes, that turned out to work. With CONFIG_DEBUG_SPINLOCK on, it goes bang > every time. With the patch, the problem goes away. > > Without CONFIG_DEBUG_SPINLOCK we're going into undefined behaviour, so > Torbjorn you're only seeing the oops occassionally (and which is why it has > not been observed or reported before). > > Thanks, > > Sean > FYI i have tested this patch for a while now and have not seen any more kernel oops. So it appears to be working.