[Bug 31090] New: Wine overwrites dyld debug information

http://bugs.winehq.org/show_bug.cgi?id=31090

Bug #: 31090
           Summary: Wine overwrites dyld debug information
           Product: Wine
           Version: 1.5.7
          Platform: x86
        OS/Version: Mac OS X
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: loader
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
    Classification: Unclassified

I've been trying to get windbag --gdb working on OS X. There seem to be
multiple issues, but a major one is that it can't load the debug headers needed
to get information out of the debugged processes.

What happens is that dbghelp/macho_module tries to read memory from the symbol
_dyld_all_image_infos in the target process. Turns out this symbol is always at
the address 0x8fe340e0, at least on my machine.

Looking with vmmap on a running wine process, this address is in an unreadable
mapping:

VM_ALLOCATE            82000000-8d9f0000 [185.9M] ---/rwx SM=NUL

which I traced to

void mmap_init(void)
{
...
    if (base > user_space_limit) reserve_area( user_space_limit, base );
}

before this call the region points to /usr/lib/dyld:
__DATA                 8fe33000-8fe38000 [   20K] rw-/rwx SM=COW  /usr/lib/dyld

but after it is as above.

But I'm afraid I don't know how to fix it. I tried adding

wine_mmap_add_reserved_area( (void*)0x82000000, 0x8ff2c000 - 0x82000000 );

to loader/main.c but it didn't seem to help. So I'm writing this bug report,
hoping someone else is able to fix it.

[Bug 31090] Wine overwrites dyld debug information

http://bugs.winehq.org/show_bug.cgi?id=31090

--- Comment #1 from Per Johansson  2012-06-30 17:31:35 CDT ---
Hrm, not sure why it said the wrong address in that copy paste, I've been
experimenting a bit... correct one should be

VM_ALLOCATE            82000000-8fe00000 [222.0M] ---/rwx SM=NUL

[Bug 31090] Wine overwrites dyld debug information

http://bugs.winehq.org/show_bug.cgi?id=31090

--- Comment #2 from Per Johansson  2012-06-30 17:34:45 CDT ---
Alright, now I'm looking like a fool... it's past bedtime here if it's an
excuse. Anyway the problem is there, even if I can't seem to find the right
values right now. If someone is willing to try to reproduce I'd be grateful.

[Bug 31090] Wine overwrites dyld debug information

http://bugs.winehq.org/show_bug.cgi?id=31090

--- Comment #3 from Per Johansson  2012-06-30 17:42:39 CDT ---
Created attachment 40812
  --> http://bugs.winehq.org/attachment.cgi?id=40812
Debug info patch

[Bug 31090] Wine overwrites dyld debug information

http://bugs.winehq.org/show_bug.cgi?id=31090

--- Comment #4 from Per Johansson  2012-06-30 17:43:34 CDT ---
You might need to use the attached patch to see the vmmap. That's where I saw
it overlap the dyld one.

[Bug 31090] Wine overwrites dyld debug information

http://bugs.winehq.org/show_bug.cgi?id=31090

Ken Thomases  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]

--- Comment #5 from Ken Thomases  ---
Please retest with Wine 1.7.8 or later.  In particular, this patch
http://source.winehq.org/git/wine.git/?a=commit;h=1577fb6c3f5941a9b2ba1fec7e38e61cdfa2b757
may have helped.

dbghelp/macho_module assumed that _dyld_all_image_infos was always at a fixed
address for any given build of the OS.  Basically, it looked up the symbol in
the symbol table of /usr/lib/dyld and used that static address.

However, in recent versions of the OS, dyld is loaded at a random address for
security (Address Space Layout Randomization).  Therefore, dbghelp/macho_module
was looking in the wrong place.

I suspect that Wine was not re-allocating the memory occupied by dyld.  It's
just that you were misled to look at the wrong memory range by the invalid
assumption embedded in dbghelp.

[Bug 31090] Wine overwrites dyld debug information

https://bugs.winehq.org/show_bug.cgi?id=31090

Austin English  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |ABANDONED

--- Comment #6 from Austin English  ---
Abandoned, potentially fixed.

[Bug 31090] Wine overwrites dyld debug information

https://bugs.winehq.org/show_bug.cgi?id=31090

Austin English  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #7 from Austin English  ---
Closing.