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SubjectRe: [PATCH v3 1/2] kretprobe: produce sane stack traces
On 2018-11-02, Aleksa Sarai <cyphar@cyphar.com> wrote:
> Unfortunately, I'm having a lot of trouble understanding how the current
> ftrace hooking works -- ORC has a couple of ftrace hooks that seem
> reasonable on the surface but I don't understand (for instance) how
> HAVE_FUNCTION_GRAPH_RET_ADDR_PTR *actually* works. Though your comment
> appears to indicate that it doesn't work for stack traces?

Sorry, I just figured out how it works! (To make sure I actually
understand -- retp is a pointer to the place in the stack where the
return address is stored, so it uniquely specifies what each trampoline
actually points to -- this trick could also be used for kretprobes).

--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>
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