Segfaults when building, running

[jasonmhite]

I'm getting segmentation faults when trying to build on 64-bit Arch Linux. At first, the Arch PKGBUILD file from here was failing with an error

/bin/sh: line 1: 28546 Segmentation fault      (core dumped) /home/jmhite/Build/julia-git/src/julia/usr/bin/julia-release-readline -bf sysimg.jl

and I thought it was because of using makepkg instead of building it directly. So, I tried directly building from a Git clone, but I get the same error. I've tried various combinations of using and not using system libraries, ranging from using no system libraries to using pretty much all system libraries, also with and without MKL, but the error is the same. Note that in particular I tried both using and not using the system version of readline since that was mentioned in the docs.

Anyway, I thought I would try it on a different computer. This one is configured very similarly to the problem machine, except the build works just fine on this one! The only real difference I can think of is that the working computer is a second-gen Intel i7 whereas the problem child is a fourth-gen i7. They have pretty similar sets of packages installed and as far as I remember are otherwise configured very similarly.

Also, I tried copying the successfully built package from the working machine to the problem machine and installing it. The Julia REPL runs fine and I can even do basic stuff like 1+1, but if I try to do some other things it segfaults. E.g., doing Pkg.install("ZMQ") segfaults and exits. But, on the other machine the same command works fine...

What on earth is going on?

[staticfloat]

Interesting, Can you cd to <julia_root>/base, (where <julia_root> is the root of the git repository) and run /home/jmhite/Build/julia-git/src/julia/usr/bin/julia-release-readline -bf sysimg.jl, and post the output of everything it spits out? If nothing too interesting gets spit out, can you gist the output of strace /home/jmhite/Build/julia-git/src/julia/usr/bin/julia-release-readline -bf sysimg.jl? That will give us an idea of what libraries are being used by Julia while trying to build the system image.

It sounds to me like there is some incompatible library that is being loaded by Julia on one machine, but not on the other, although it's possible there is a problem with the CPU architecture as well. What git hash is your julia building? (git rev-parse HEAD inside of the Julia git repo will give you that)

[jasonmhite]

All I get from running it directly is

could not open file boot.jl[1]    3149 segmentation fault (core dumped)  ./julia-release-readline -bf sysimg.jl

So, I did a stack trace like you asked for here. The git SHA is b6b4f02.

Both the working and non-working system should have the same libraries and versions installed, which should pretty much be the latest versions, whatever is available in the Arch repos. I can give you a list of installed packages on both machines if you like. But, I also tried building with no system libraries at all and it still failed.

Thanks for the help so far!

[jasonmhite]

Oh, I see in that stack trace that it's trying to load the version of readline that is shipped with the Intel compilers, I wonder if maybe that is the problem?

Interestingly, if I run julia-release-readline on the working system it also segfaults. For some reason it doesn't seem to kill the build process on that machine (or have any real effect).

[staticfloat]

Is there a boot.jl in <julia_root>/base/? Additionally, you need to run julia-release-readline within the base directory.

[jasonmhite]

Ah, ok. There is a boot.jl. I was not running it in the base directory, here's the output when I do:

exports.jl
base.jl
reflection.jl
promotion.jl
build_h.jl
c.jl
range.jl
tuple.jl
cell.jl
expr.jl
error.jl
bool.jl
number.jl
int.jl
operators.jl
pointer.jl
float.jl
reduce.jl
complex.jl
rational.jl
abstractarray.jl
subarray.jl
array.jl
bitarray.jl
intset.jl
dict.jl
set.jl
iterator.jl
inference.jl
osutils.jl
[1]    6386 segmentation fault (core dumped)  ../usr/bin/julia-release-readline -bf sysimg.jl

And the stack trace.

[staticfloat]

Interesting. Can you build a debug version of Julia (make debug in the main Julia directory), which will likely fail during system image generation again, but the executable will be sitting in <julia_root>/usr/bin/, called julia-debug-readline or somesuch. We'll use that path to build the system executable inside of gdb:

$ cd base/
$ gdb --args ../usr/bin/julia-debug-readline -bf sysimg.jl

Once gdb starts up, just hit r to run the program. It'll crash eventually, at which you'll have a (gdb) prompt, and if you enter bt it will print out a backtrace showing us where in process execution failed. Please post that backtrace, it would be most helpful!

[jasonmhite]

Here's the backtrace.

I can dig through with GDB more if you tell me what to look for.

[Keno]

Try commenting in the call to verifyFunction in gf.c and see what happens.

[jasonmhite]

There isn't a call to verifyFunction in src/gf.c. A quick grep of the code says that verifyFunction only appears in codegen.cpp, around line 251 (and it's already commented out). We're talking about this file and this one, right?

[staticfloat]

Yes. Comment that back in and remake.
On Aug 1, 2013 5:21 PM, "jasonmhite" notifications@github.com wrote:

There isn't a call to verifyFunction in src/gf.c. A quick grep of the code
says that verifyFunction only appears in codegen.cpp, around line 251 (and
it's already commented out). We're talking about this filehttps://github.com/JuliaLang/julia/blob/master/src/gf.cand this
one https://github.com/JuliaLang/julia/blob/master/src/codegen.cpp,
right?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/3899#issuecomment-21979323
.

[staticfloat]

EDIT: I suppose I should say, (Un)comment that back in and remake. Also, I would do the one before the FPM->run(*f); that is, the one on line 252.

[jasonmhite]

Sorry for the delay, I was on a business trip.

I commented in lines 251-252 and 256-259 of codegen.cpp. Note that I left line 254 commented out as it gives an error that n_compile is not declared if I leave it in.

Here's the full output from running make.

[jasonmhite]

Incidentally, I tried building one of the source tarballs (v0.1.2) and I think some of the links that the makefile fetches dependencies from are broken. Wget gives me access denied messages.

[StefanKarpinski]

We don't, as far as I know, support building from tarballs. GitHub insists on providing tarball downloads, but that isn't a supported way to build julia – if you want to build from source, you have to use git.

[jasonmhite]

Makes sense. I just wanted to see if the old version would build, but I guess it doesn't matter.