Comment 0 for bug 1731325

In one of our applications, we use dlopen to open a bunch of DLL files in the following order:

1. zlib 1.2.8 version (not the one bundled in Ubuntu 17.10)
2. gtk-x11-2.0.so.0 bundled in the system
3. libSM.so.6 bundled in the system

The dlopen api crashes with 'Segmentation fault' when opening libSM.so.6. You can reproduce the issue using the following simple program.

Sample C program:
=================
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>

int
main(int argc, char **argv)
{
  int i;
  for (i = 1; i < argc; i++) {
   void *handle;
   printf("Opening %s\n", argv[i]);
   handle = dlopen(argv[i], RTLD_LAZY | RTLD_LOCAL);
    if (!handle) {
        printf("Error: %s\n", dlerror());
    }
  }
  exit(EXIT_SUCCESS);
}

Compile and run as follows:
$ ./a.out /path/to/libz/versio/1.2.8 /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0 libSM.so.6

Note:
- We encountered this issue only in Ubuntu 17.10. In ubuntu 17.04, we didn't have any issue. May be this is an issue with the latest glibc. Not sure.

Investigation done:
- dlopen initially passes while opening zlib version.
- dlopen fails to open libgtk-x11-2.0.so.0 with the following error:

Error: /usr/lib/vmware-tools/lib/libz.so.1/libz.so.1: version `ZLIB_1.2.9' not found (required by /usr/lib/x86_64-linux-gnu/libpng16.so.16)

And then dlopen for libSM.so.6 core dumps.

I understand that the zlib 1.2.8 doesn't provide the necessary required version and hence dlopen for gtk failed. But why does dlopen crash for libSM.so.6?

- I executed valgrind command and attaching the output.

Please let me know if any other information is required.

Thanks
Sankar.