[PATCH v2 3/3] btrace, frame: fix crash in get_frame_type
Pedro Alves
palves@redhat.com
Tue Feb 9 22:01:00 GMT 2016
On 02/09/2016 02:42 PM, Metzger, Markus T wrote:
>>> CORE_ADDR frame_unwind_pc (struct frame_info *this_frame) {
>>> + if (this_frame == NULL)
>>> + throw_error (NOT_AVAILABLE_ERROR, _("PC not available"));
>>
>> How can this happen?
>
> One of its callers, frame_unwind_caller_pc, calls it with the result of
> skip_artificial_frames like this:
>
> CORE_ADDR
> frame_unwind_caller_pc (struct frame_info *this_frame)
> {
> return frame_unwind_pc (skip_artificial_frames (this_frame));
> }
>
> Rather than handling the skip_artificial_frames() NULL return here,
> I made frame_unwind_pc handle a NULL frame argument.
>
> I can move the check into frame_unwind_caller_pc if you prefer.
Yes, please.
Though, I think all these frame_unwind_caller_XXX methods should be
consistent in how they handle skip_artificial_frames (this_frame)
returning NULL, because they're all called together, assuming they're
referring to the same frame. If we throw error here, then I think
we should throw in frame_unwind_caller_arch too, instead of having
that one return the arch of the next frame.
Thanks,
Pedro Alves
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