linux-kernel - Re: [alsa-devel] [PATCH v2] soundwire: stream: fix bad unlock balance

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 6 Jun 2019 10:36:02 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        vkoul@...nel.org
Cc:     Sanyog Kale <sanyog.r.kale@...el.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: [alsa-devel] [PATCH v2] soundwire: stream: fix bad unlock balance

On 6/6/19 9:58 AM, Srinivas Kandagatla wrote:
> 
> 
> On 06/06/2019 15:28, Pierre-Louis Bossart wrote:
>> On 6/6/19 6:22 AM, Srinivas Kandagatla wrote:
>>> multi bank switching code takes lock on condition but releases without
>>> any check resulting in below warning.
>>> This patch fixes this.
>>
>>
>> Question to make sure we are talking about the same thing: multi-link 
>> bank switching is a capability beyond the scope of the SoundWire spec 
>> which requires hardware support to synchronize links and as Sanyog 
>> hinted at in a previous email follow a different flow for bank switches.
>>
>> You would not use the multi-link mode if you have different links that 
>> can operate independently and have no synchronization requirement. You 
>> would conversely use the multi-link mode if you have two devices on 
>> the same type on different links and want audio to be rendered at the 
>> same time.
>>
>> Can you clarify if indeed you were using the full-blown multi-link 
>> mode with hardware synchronization or a regular single-link operation? 
>> I am not asking for details of your test hardware, just trying to 
>> reconstruct the program flow leading to this problem.
>>
> 
> Am testing on a regular single link, which hits this path.
> 
>> It could also be that your commit message was meant to say:
>> "the msg lock is taken for multi-link cases only but released 
>> unconditionally, leading to an unlock balance warning for single-link 
>> usages"?
> Yes.

Thanks for the precision. the change is legit so assuming the commit 
message is reworded to mention single link usage please feel free to 
take the following tag.

Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>

Thanks!