Re: Darafei "Komяpa" Praliaskouski 2018-07-23 <CAC8Q8t+=17oz4tzgcpn-1batco0_45tbxoc2assg1y9a9b6...@mail.gmail.com> > > It looks to me like it's a LLVM issue, specifically > > https://bugs.llvm.org/show_bug.cgi?id=34424 > > fixed in LLVM 5+. > > > > Thank you for your investigation.
Thanks! > > It'll only be an issue for extensions that throw c++ style exceptions. I > > don't think that rises to the level of disallowing any LLVM version < > > 5.0. I suggest postgis adds an error check to its buildprocess that > > refuses to run if jit is enabled and a too old version is used? > > Unfortunately that's not an option. Is it possible to disable JIT per extension, say by removing all .bc files for it, or via a PGXS variable? Or does this bug still trigger even without the .bc files for PostGIS? > If Christoph decides to keep LLVM enabled for 11 on that platform, as he is > recommended upthread by Tom, that would mean that PostGIS can't be packaged > at all, and all the people who need it will have to stay on Postgres 10. We'll definitely need to find a proper fix, not shipping PostGIS is not an option. > If PostGIS decides not to implement the check, and instead tweaks test > runner to execute `set jit to off;` before tickets.sql, then Postgres 11 on > that platform will have a known way to segfault it, even without superuser > rights, as jit GUC is tweakable by anyone. Not a good option, ack. > I think that a good way to deal with it will be to bump minimum required > version of LLVM to 5 on Postgres build, with a notice in docs that will say > that "you can build with lower version, but that will give you this and > this bug". Is LLVM << 5 generally acceptable for use with PostgreSQL, or should we look into getting a new version to distribute along with it on apt.postgresql.org? I'd rather like to avoid having to ship a compiler... > It also may happen that a patch for LLVM can be applied to LLVM4 build in > Debian and brought in as an update, but such a plan should not be a default > one. That's actually a plan I like very much. Hopefully the patch is small and backpatchable. Christoph