objtool warnings on 4.14-stable/gcc-7.3.0

[Arnd Bergmann]

Hi Josh,

I recently did some randconfig testing with a plain 4.14-stable kernel
and gcc-7.3.0, and came across three distinct objtool warnings:

drivers/misc/lkdtm_bugs.o: warning: objtool:
lkdtm_CORRUPT_LIST_ADD()+0x15: return with modified stack frame

crypto/asymmetric_keys/x509_cert_parser.o: warning: objtool:
x509_note_pkey_algo()+0xa4: sibling call from callable instruction
with modified stack frame

drivers/infiniband/hw/bnxt_re/qplib_fp.o: warning: objtool:
bnxt_qplib_poll_cq()+0x106: sibling call from callable instruction
with modified stack frame

It's likely that this is the complete set at the moment, I saw each
one multiple times,
but did not see any others. I'll reply with the respective object
files for your reference,
in case these are so far unknown to you. There are only a handful of randconfig
warnings we see overall in the kernel these days (at least on x86 and arm64), so
even if they are false-positive, it would be great to get rid of the
output so we can
do randconfig testing on 4.14.y and treat any output from 'make -s' as
a regression.
I did not check

With gcc-8, things are looking very differently, and we still get an
endless supply of
similar warnings.

        Arnd