Re: valgrind error

Noah Misch <noah@leadboat.com> writes:
> I can reproduce this on a 2017-vintage CPU with ./configure
> ... USE_SLICING_BY_8_CRC32C=1 and then running "make installcheck-parallel"
> under valgrind-3.15.0 (as packaged by RHEL 7.8).  valgrind.supp has a
> suppression for CRC calculations, but it didn't get the memo when commit
> 4f700bc renamed the function.  The attached patch fixes the suppression.

I can also reproduce this, on RHEL 8.2 which likewise has valgrind-3.15.0,
using the same configuration to force use of that CRC function.  I concur
with your diagnosis that this is just a missed update of the pre-existing
suppression rule.  However, rather than

-       fun:pg_comp_crc32c
+       fun:pg_comp_crc32c*

as you have it, I'd prefer to use

-       fun:pg_comp_crc32c
+       fun:pg_comp_crc32c_sb8

which precisely matches what 4f700bc did.  The other way seems like
it's giving a free pass to problems that could lurk in unrelated CRC
implementations.

            regards, tom lane