Re: 1.5.21-1 DLL Loading Problem

[Martin <linkscrazy at yahoo dot com>]

--- Rob Hatcherson <rob.hatcherson@zedasoft.com> wrote:

> All:
> 
> After installing 1.5.21-1 (cygcheck output attached) I've starting 
> experiencing a DLL loading problem whose presentation is similar to
> that 
> of a problem described by Gary Zablackis in a 12-Apr-2006 post with 
> subject "Patch for silent crash with Cygwin1.dll v 1.5.19-4".  
> Examination of dll_init.cc shows that some variation of the suggested
> 
> patch is part of 1.5.21-1.
> 
> 
> The general situation is that I have a program that depends on
> "B.dll", 
> which in turn depends on "A.dll".  Both DLLs provide C++ classes. 
> The 
> symptom is that an attempt to launch the program comes back to the
> shell 
> prompt without doing anything, i.e. no error messages, no output, no 
> anything else.  If I statically link the program then it always
> works.
> 
> 
> Attempts to run in gdb in the dynamically linked case result in
> output 
> similar to this:
> 
> Starting program: /cygdrive/c/WorkAreas/...
> 
> Program received signal SIGSEGV, Segmentation fault.
> Error: dll starting at 0x4d1000 not found.
> 
> Program received signal SIGSEGV, Segmentation fault.
> 
> Program received signal SIGSEGV, Segmentation fault.
> 
> Program exited with code 030000000005.
> You can't do that without a process to debug.
> 
> 
> The line "dll starting at 0x4d1000 not found" seemed to suggest that
> I 
> have a path issue, but by inspection I don't believe this is the
> case, 
> plus if I move the DLLs in question out of the way I get a different 
> response from gdb.
> 
> 
> Google'ing hasn't yielded much yet.  The post I referenced above is
> the 
> closest thing I've found so far to the symptom I'm seeing.
> 
> I've been trying to track this down with gdb, but haven't made much 
> progress.  I put the cygwin1.dbg from the src distro into the /bin
> dir, 
> which at least allowed some level of breakpoint setting, but so far
> none 
> of the ones I've tried (dlopen, dll::init(), and a few others in that
> 
> vicnity) have been hit.  I'm not too familiar with the cygwin source 
> base, so I may be snooping around in the wrong spot.
> 
> I've also been working on reducing the scenario down to some very
> simple 
> libraries that reproduce the symptom reliably, but this hasn't
> yielded 
> anything worth reporting yet.
> 
> 
> In the meantime, does anyone have any suggestions regarding what's
> going 
> on, and/or some other technique to catch this problem?
> 
> Rob
> 
=== message truncated ===> --

I had a similar problem with dynamically loaded modules (extensions) in
TCL.  I traced my problem to the upgrade of binutils 20050610-1 to
binutils 20060709-1.  When I rolled it back, everthing was fine.

However, I'm still running 1.5.20-1.

Hope this helps,
Martin


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