Re: [PATCH] ACPICA: cleanup method properly on error

[Vegard Nossum]

On 07/26/2016 10:28 PM, Moore, Robert wrote:
>      /* Put the new state at the head of the walk list */
>
>      if (Thread)
>      {
>          AcpiDsPushWalkState (WalkState, Thread);
>      }
>
> Is there any chance that Thread could be zero?

I'm not sure if this question was for me or not, but that code (modulo
the capitalisation differences) is the reason why I also used 'if
(thread)' in my patch.


Vegard

> > -----Original Message-----
> > From: Devel [mailto:devel-bounces@xxxxxxxxxx] On Behalf Of Moore, Robert
> > Sent: Tuesday, July 26, 2016 7:40 AM
> > To: Vegard Nossum <vegard.nossum@xxxxxxxxxx>; Zheng, Lv
> > <lv.zheng@xxxxxxxxx>; Wysocki, Rafael J <rafael.j.wysocki@xxxxxxxxx>
> > Cc: linux-acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > stable@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx
> > Subject: Re: [Devel] [PATCH] ACPICA: cleanup method properly on error
> >
> > We'll look at this.
> > Thanks.
> >
> >
> > > -----Original Message-----
> > > From: Vegard Nossum [mailto:vegard.nossum@xxxxxxxxxx]
> > > Sent: Friday, July 22, 2016 8:35 AM
> > > To: Moore, Robert <robert.moore@xxxxxxxxx>; Zheng, Lv
> > > <lv.zheng@xxxxxxxxx>; Wysocki, Rafael J <rafael.j.wysocki@xxxxxxxxx>
> > > Cc: linux-acpi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; linux-
> > > kernel@xxxxxxxxxxxxxxx; Vegard Nossum <vegard.nossum@xxxxxxxxxx>;
> > > stable@xxxxxxxxxxxxxxx
> > > Subject: [PATCH] ACPICA: cleanup method properly on error
> > >
> > > If the call to acpi_ds_init_aml_walk() fails, then we have to undo the
> > > walk state push done by acpi_ds_create_walk_state(). Otherwise, the
> > > new walk state (which has just been freed) will remain on the thread's
> > > walk_state_list and be dereferenced in acpi_ps_parse_aml() when we try
> > > to get the new state.
> > >
> > > You can observe this when reading e.g.
> > >
> > >      /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0F:01/status
> > >
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
> > > ---
> > >   drivers/acpi/acpica/dsmethod.c | 2 ++
> > >   1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/acpi/acpica/dsmethod.c
> > > b/drivers/acpi/acpica/dsmethod.c index 47c7b52..44b50a6 100644
> > > --- a/drivers/acpi/acpica/dsmethod.c
> > > +++ b/drivers/acpi/acpica/dsmethod.c
> > > @@ -596,6 +596,8 @@ cleanup:
> > >   	/* On error, we must terminate the method properly */
> > >
> > >   	acpi_ds_terminate_control_method(obj_desc, next_walk_state);
> > > +	if (thread)
> > > +		acpi_ds_pop_walk_state(thread);
> > >   	acpi_ds_delete_walk_state(next_walk_state);
> > >
> > >   	return_ACPI_STATUS(status);
> > > --
> > > 1.9.1
> >
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