Re: [RFC PATCH v2 1/8] arm64: Implement stack trace termination record

On 3/19/21 9:29 AM, Madhavan T. Venkataraman wrote:

On 3/19/21 7:30 AM, Mark Brown wrote:

quoted

On Thu, Mar 18, 2021 at 03:26:13PM -0500, Madhavan T. Venkataraman wrote:

quoted

On 3/18/21 10:09 AM, Mark Brown wrote:

quoted

quoted

If we are going to add the extra record there would probably be less
potential for confusion if we pointed it at some sensibly named dummy
function so anything or anyone that does see it on the stack doesn't get
confused by a NULL.

quoted

I agree. I will think about this some more. If no other solution presents
itself, I will add the dummy function.

After discussing this with Mark Rutland offlist he convinced me that so
long as we ensure the kernel doesn't print the NULL record we're
probably OK here, the effort setting the function pointer up correctly
in all circumstances (especially when we're not in the normal memory
map) is probably not worth it for the limited impact it's likely to have
to see the NULL pointer (probably mainly a person working with some
external debugger).  It should be noted in the changelog though, and/or
merged in with the relevant change to the unwinder.

OK. I will add a comment as well as note it in the changelog.

Thanks to both of you.

Madhavan

I thought about this some more. I think I have a simple solution. I will
prepare a patch and send it out. If you and Mark Rutland approve, I will
include it in the next version of this RFC.

Madhavan

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