Re: [PATCH 09/30] coresight: cpu-debug: Replace mutex with mutex_trylock on panic notifier

[Suzuki K Poulose <suzuki.poulose@xxxxxxx>]

Hi

On 09/05/2022 14:09, Guilherme G. Piccoli wrote:
> On 28/04/2022 05:11, Suzuki K Poulose wrote:
> > Hi Guilherme,
> >
> > On 27/04/2022 23:49, Guilherme G. Piccoli wrote:
> > > The panic notifier infrastructure executes registered callbacks when
> > > a panic event happens - such callbacks are executed in atomic context,
> > > with interrupts and preemption disabled in the running CPU and all other
> > > CPUs disabled. That said, mutexes in such context are not a good idea.
> > >
> > > This patch replaces a regular mutex with a mutex_trylock safer approach;
> > > given the nature of the mutex used in the driver, it should be pretty
> > > uncommon being unable to acquire such mutex in the panic path, hence
> > > no functional change should be observed (and if it is, that would be
> > > likely a deadlock with the regular mutex).
> > >
> > > Fixes: 2227b7c74634 ("coresight: add support for CPU debug module")
> > > Cc: Leo Yan <leo.yan@xxxxxxxxxx>
> > > Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> > > Cc: Mike Leach <mike.leach@xxxxxxxxxx>
> > > Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > > Signed-off-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxx>
> > How would you like to proceed with queuing this ? I am happy
> > either way. In case you plan to push this as part of this
> > series (I don't see any potential conflicts) :
> >
> > Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Hi Suzuki, some other maintainers are taking the patches to their next
> branches for example. I'm working on V2, and I guess in the end would be
> nice to reduce the size of the series a bit.
>
> So, do you think you could pick this one for your coresight/next branch
> (or even for rc cycle, your call - this is really a fix)?
> This way, I won't re-submit this one in V2, since it's gonna be merged
> already in your branch.
I have queued this to coresight/next.

Thanks
Suzuki