On Wed, Aug 09, 2023 at 12:33:17PM -0700, Florian Fainelli wrote:
> On 8/9/23 03:40, Greg Kroah-Hartman wrote:
> > From: Cristian Marussi <cristian.marussi@xxxxxxx>
> >
> > [ Upstream commit d1ff11d7ad8704f8d615f6446041c221b2d2ec4d ]
> >
> > SCMI transport based on SMC can optionally use an additional IRQ to
> > signal message completion. The associated interrupt handler is currently
> > allocated using devres but on shutdown the core SCMI stack will call
> > .chan_free() well before any managed cleanup is invoked by devres.
> > As a consequence, the arrival of a late reply to an in-flight pending
> > transaction could still trigger the interrupt handler well after the
> > SCMI core has cleaned up the channels, with unpleasant results.
> >
> > Inhibit further message processing on the IRQ path by explicitly freeing
> > the IRQ inside .chan_free() callback itself.
> >
> > Fixes: dd820ee21d5e ("firmware: arm_scmi: Augment SMC/HVC to allow optional interrupt")
> > Reported-by: Bjorn Andersson <andersson@xxxxxxxxxx>
> > Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
> > Link: https://lore.kernel.org/r/20230719173533.2739319-1-cristian.marussi@xxxxxxx
> > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> > drivers/firmware/arm_scmi/smc.c | 17 +++++++++++------
> > 1 file changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
> > index 4effecc3bb463..f529004f1922e 100644
> > --- a/drivers/firmware/arm_scmi/smc.c
> > +++ b/drivers/firmware/arm_scmi/smc.c
> > @@ -21,6 +21,7 @@
> > /**
> > * struct scmi_smc - Structure representing a SCMI smc transport
> > *
> > + * @irq: An optional IRQ for completion
> > * @cinfo: SCMI channel info
> > * @shmem: Transmit/Receive shared memory area
> > * @shmem_lock: Lock to protect access to Tx/Rx shared memory area
> > @@ -30,6 +31,7 @@
> > */
> > struct scmi_smc {
> > + int irq;
>
> For this backport to apply as-is and not define a duplicate "int irq" field
> we need to take in f716cbd33f038af87824c30e165b3b70e4c6be1e ("firmware:
> arm_scmi: Make smc transport use common completions") which did remove the
> "int irq" from struct scmi_smc.
>
> Alternatively, we can just omit this hunk adding the "int irq" member from
> the back port.
>
There is a bit disconnect in the communication here. I didn't see Greg was
not cc-ed on the earlier email to Sasha[1]. The request to drop it was also
made here[2].
> This is a 5.15 stable kernel problem only because
> f716cbd33f038af87824c30e165b3b70e4c6be1e is in v5.18 and newer.
--
Regards,
Sudeep
[1] https://marc.info/?l=linux-stable-commits&m=169159392424103&w=2
(couldn't find a lore link for the above)
[2] https://lore.kernel.org/all/ZNIdrd+SQ0KjYWKA@e120937-lin/
