Ingo Molnar [off-list ref] writes:

* Eric W. Biederman [off-list ref] wrote:

quoted

Looking deeper it was discovered that si_trapno is used for only
a few select signals on alpha and sparc, and that none of the
other _sigfault fields past si_addr are used at all.  Which means
technically no regression on alpha and sparc.

If there's no functional regression on any platform, could much of this 
wait until v5.14, or do we want some of these cleanups right now?

The fixes seem to be for long-existing bugs, not fresh regressions, AFAICS. 
The asserts & cleanups are useful, but not regression fixes.

I.e. this is a bit scary:

The new ABI for SIGTRAP TRAP perf that came in the merge window is
broken and wrong.  We need to revert/disable the new SIGTRAP TRAP_PERF
or have a fix before v5.13.

The issue is old crap getting in the way of a new addition.  I think I
might see a smaller code change on how to get to something compatible
with this.

quoted

 32 files changed, 377 insertions(+), 163 deletions(-)

at -rc2 time.

The additions are all tests to make certain everything is fine.
The actual code change without the assertions (tests) is essentially
a wash.

Eric