From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Salyzyn Subject: Re: [PATCH v2] ALSA: seq: resize buffer for overflow Date: Mon, 9 Oct 2017 07:51:40 -0700 Message-ID: References: <20171006171731.88889-1-salyzyn@android.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Takashi Iwai Cc: linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org, bunk@kernel.org, Jaroslav Kysela , bunk@stusta.de List-Id: alsa-devel@alsa-project.org On 10/07/2017 02:39 AM, Takashi Iwai wrote: > I doubt it came from snd_midi_event_encode_byte(). > Judging from the call trace below, the event originated from the OSS > sequencer write, i.e. it received an OSS event packet, and it was > delivered again to another OSS sequencer port back via dummy client. > > If so, it should have received some EV_SYSEX packet, and it was > processed via snd_seq_oss_synth_sysex(), and the encoded event was > delivered. > > Now the question is how it triggers this Oops. I couldn't find any > obvious cause, but one thing I noticed is a possible race when writing > to OSS sequencer concurrently. Something wrong might happen. Concurrent writing, thanks, I will switch gears and see if that represents the replication path! > BTW, about your patch is buggy regarding the call kmalloc() with > GFP_KERNEL inside spinlock. yup, withdraw this patch, and please erase it from my permanent record ;-> Thanks for the review, it was immensely helpful! -- Mark