Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | Re: Oops in ACPI with git latest | Date | Fri, 24 Oct 2008 08:57:17 +0200 |
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On Friday, 24 of October 2008, James Bottomley wrote: > On Thu, 2008-10-23 at 15:34 -0700, Moore, Robert wrote: > > + if (!output.pointer) > > + return AE_NULL_OBJECT; > > + > > > > This probably won't work. acpi_evaluate_object currently doesn't touch the pointer parameter if there is no return value, it only sets the length to zero. > > Actually, it does.
Well, this was the only candidate for a NULL pointer dereference, so I'd be surprised if it didn't. :-)
> > So, you might try this: > > > > + if (!output.length) > > + return AE_NULL_OBJECT; > > +
Still, I'd expect the AML interpreter to return error code in this case.
> This also works.
Why don't we make it extra safe, then. ;-)
--- From: Rafael J. Wysocki <rjw@sisk.pl> Subject: Prevent acpi_osc_run from using NULL objects
Check if the object returned by acpi_evaluate_object() in acpi_run_osc() is not NULL.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> --- drivers/pci/pci-acpi.c | 3 +++ 1 file changed, 3 insertions(+)
Index: linux-2.6/drivers/pci/pci-acpi.c =================================================================== --- linux-2.6.orig/drivers/pci/pci-acpi.c +++ linux-2.6/drivers/pci/pci-acpi.c @@ -83,6 +83,9 @@ static acpi_status acpi_run_osc(acpi_han if (ACPI_FAILURE(status)) return status; + if (!output.pointer || !output.length) + return AE_NULL_OBJECT; + out_obj = output.pointer; if (out_obj->type != ACPI_TYPE_BUFFER) { printk(KERN_DEBUG "Evaluate _OSC returns wrong type\n");
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