[PATCH] powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64 semantics

[Raoni Fassina Firmino]

On Tue, Feb 02, 2021 at 05:41:35PM +1000, Nicholas Piggin wrote:
> Are you planning to update glibc to cope with this as well? Any idea 
> about musl? If so, including version numbers would be good (not that
> it's really a problem to carry this patch around).

For glibc from the beginning I planned to send a patch as well and
fortunately it got in[1] in time for yesterday's 2.33 release.  That
patch is meant to address kernels 5.9 and 5.10 but is also compatible
with older kernels and with this patch. So everyone should be compatible
with everyone else :-) (except unpatched kernels 5.9 and 5.10 with
unpatched glibcs prior to 2.33)

I don't know about musl, I took a look and maybe wrong here but didn't
find any backtrace() implementation and it seems that it uses its own
return code for the trampoline, but I am not sure.

Rich mentioned[2] that he didn't see how it would break musl and was
waiting for feedback from ppc users to be sure.

Thanks for the review :-)

o/
Raoni

[1] https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=5ee506ed35a2c9184bcb1fb5e79b6cceb9bb0dd1
[2] https://lists.ozlabs.org/pipermail/linuxppc-dev/2021-January/223198.html