On Tue, Feb 14, 2017 at 6:22 PM, Adar Dembo wrote:
> Any idea why this only surfaced recently? There's a call to
> std::call_once in util/logging.cc that's been there for almost a year.
>
I'm guessing that one is only very rarely called (on crash) and would only
be called by multiple threads at
Any idea why this only surfaced recently? There's a call to
std::call_once in util/logging.cc that's been there for almost a year.
In any case, I'm not a huge fan of #2. #1 and #3 both require a patch,
but I think #1 is more likely to get noticed (and reverted) upon an
LLVM 4.0 upgrade. So I think
BTW, I should add that libstdcxx as included in gcc 4.9.2 (devtoolset on
el6) doesn't have this bug, since it just wraps pthread_once. So, it's
probably not a _real_ issue since we don't use libc++ for production builds.
-Todd
On Tue, Feb 14, 2017 at 6:05 PM, Todd Lipcon wrote:
> I noticed that
I noticed that a lot of our tests have gotten flaky with a TSAN race
reported around SSL initialization. After digging into a bit, I found that
our version of libcxx has a bug in std::once where it's using a relaxed
load instead of an acquire load to check the flag of whether it has run yet.
I wen
