Re: [PATCH] mailbox: pcc: Synchronize channel IRQ before unmapping shared memory

[Sudeep Holla]

On Thu, Sep 03, 2026 at 10:51:28AM +0100, Christian Loehle wrote:
> On 9/3/26 10:10, Sudeep Holla wrote:
> > On Thu, Sep 03, 2026 at 10:03:38AM +0100, Sudeep Holla wrote:
> >> On Fri, Aug 28, 2026 at 05:10:33PM +0100, Christian Loehle wrote:
> >>> pcc_mbox_free_channel() unmaps the PCC shared-memory region before
> >>> mbox_free_channel() invokes the controller shutdown callback. For
> >>> interrupt-capable extended subspaces, an in-flight handler may
> >>> consequently access the mapping after it has been invalidated.
> >>>
> >>> Release the mailbox channel first so its IRQ is disabled and synchronized
> >>> before unmapping the shared-memory region. Serialize PCC channel
> >>> acquisition and release across this sequence: once mbox_free_channel()
> >>> makes the channel available, another client must not replace the
> >>> shared-memory mapping until the old one has been unmapped.
> >>>
> >>
> >> Breno Leitao has already posted the fix for the unmapping before freeing
> >> the channel. You just need the mutex guards.
> >>
> > 
> > Failed to add the reference to it [1] earlier.
> > 
> 
> Thanks, I didn't see that.
> I guess I'll wait until Breno's patch hits linux-next
> or linus' tree and rebase?
> 

No just post it with a dependency mention. Both can go together IMO.

-- 
Regards,
Sudeep