Shared context test crashes on psm2 when it's built as a DL provider

[arn314]

Test: fi_shared_ctx -p "psm2"

I see the following crash on psm2 provider when it's built as a separate dynamic library:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff6a9d0ed in getenv () from /lib64/libc.so.6
(gdb) bt
#0  0x00007ffff6a9d0ed in getenv () from /lib64/libc.so.6
#1  0x00007ffff63cb470 in fini_ipath_backtrace () from /lib64/libinfinipath.so.4
#2  0x00007ffff7deab7a in _dl_fini () from /lib64/ld-linux-x86-64.so.2
#3  0x00007ffff6a9da69 in __run_exit_handlers () from /lib64/libc.so.6
#4  0x00007ffff6a9dab5 in exit () from /lib64/libc.so.6
#5  0x00007ffff6a86c0c in __libc_start_main () from /lib64/libc.so.6
#6  0x0000000000401759 in _start ()

The issue is present in v1.5.0 as well.

[shefty]

This may be of interest:
https://bugzilla.redhat.com/show_bug.cgi?id=1344529
Is this verbs related code?

[j-xiong]

No. It's the user space driver interface for psm.

[j-xiong]

It's weird that the segfault happened in the psm code path while the provider being used was psm2.

[shefty]

Maybe OpenMPI is calling psm code directly, resulting in a double use of the library?

[j-xiong]

But it is not an OpenMPI test.

The code is part of the library destructor which is called when the program exits. So the code being called is probably just how the finalization process works. Anyway, segfault inside getenv is quite unusual. Either the getenv symbol is pointing to an invalid address or some memory corruption has occurred somewhere.

[shefty]

Sorry - I need to stop following so many threads at once. Yeah, we may be looking at a memory corruption from somewhere.

[j-xiong]

I think I have found the reason. Under certain condition (satisfied by the fi_shared_ctx test), the provider calls putenv() to add an environment variable to automatically turn on the PSM2 multi EP support. This works fine as a built-in provider. However, if the provider is dynamically loaded, the environment becomes corrupted after the provider is unloaded.