RFR: 8282306: os::is_first_C_frame(frame*) crashes on invalid link access [v2]

[Johannes Bechberger]

On Wed, 23 Feb 2022 19:06:05 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Johannes Bechberger has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Improve use of C macros
>
> src/hotspot/cpu/ppc/frame_ppc.inline.hpp line 120:
> 
>> 118: }
>> 119: 
>> 120: inline bool frame::can_access_link(Thread *thread) const { return true; }
> 
> Why are ppc and s390 different from other platforms? If there is a valid reason, could you please add a short comment?

Because they do not (as I see it) directly dereference a location on the stack to get to this value.

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PR: https://git.openjdk.java.net/jdk/pull/7591