[Bug 58742] New: winedbg: Internal crash at 00006FFFFF8CB5E5 (pe_load_msc_debug_info)

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=58742

Bug ID: 58742
           Summary: winedbg: Internal crash at 00006FFFFF8CB5E5
                    (pe_load_msc_debug_info)
           Product: Wine
           Version: 10.15
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: winedbg
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Platform: Linux Mint 21.3 Cinnamon
Linux Kernel: 5.15.0-156-generic
Platform 2: Linux Mint 22.2 Cinnamon
Linux Kernel 2: 6.8.0-83-generic

When I build Wine myself and run the command `$WINE winedbg explorer` with it,
it leads to a crash. This does not happen with the official builds of Wine, so
I'm guessing there's some package version difference or something along those
lines that makes this occur.

Log from a custom build of 10.15:
```
user@pc:~/wine/test$ $WINE winedbg explorer
WineDbg starting on pid 0184
0180:fixme:dbghelp:elf_search_auxv can't find symbol in module
0180:fixme:dbghelp:elf_search_auxv can't find symbol in module
winedbg: Internal crash at 00006FFFFF8CB5E5
user@pc:~/wine/test$
```

Log from the official build of 10.15:
```
user@pc:~/wine/test$ wine winedbg explorer
WineDbg starting on pid 01b4
01b0:fixme:dbghelp:elf_search_auxv can't find symbol in module
01b0:fixme:dbghelp:elf_search_auxv can't find symbol in module
0x006fffffc00c3d ntdll+0x10c3d: retq
Wine-dbg>
```

The crash occurs in pe_load_msc_debug_info from pe_module.c, in the branch with
`/* Debug info is stripped to .DBG file */`. The variable `dbg` is null, so it
crashes when trying to dereference it.

Here's a quick fix I made for it. It fixes the crash but it doesn't really
solve
the underlying issue. As a result the debugger is missing so much debug
information that it's not actually that helpful.
```
/* Read in debug directory */
dbg = RtlImageDirectoryEntryToData( mapping, FALSE,
IMAGE_DIRECTORY_ENTRY_DEBUG, &nDbg );
nDbg = dbg ? nDbg / sizeof(IMAGE_DEBUG_DIRECTORY) : 0;

/* NEW */
if (!dbg)
{
    pe_unmap_full(fmap);
    return ret;
}
/* END */

/* Parse debug directory */
```

It's a bit annoying but for the time being I'll probably use the official build
for debugging, or maybe I'll try to build Wine using the Docker set-up from the
Gitlab CI.