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Re: 1.15.19 dlopen() dies with no dlerror()

Jim Kleckner wrote:

Larry Hall (Cygwin) wrote:
Jim Kleckner wrote:

Larry Hall (Cygwin) wrote:
Jim Kleckner wrote:
Jim Kleckner wrote:
Michael McKerns wrote:
Yes, yes... I've not given you enough information...
I'm seeing a similar problem with python and 1.5.19 and also tried the snapshot of 22-May.

CYGWIN_NT-5.1 kleckner2 1.5.20s(0.155/4/2) 20060522 00:51:23 i686 Cygwin

A simple test case doesn't fail in dlopen().

My code is not simple but has been working prior to the most recent update (which also updated python and other packages).
A downrev of python does not make the problem go away. If I downrev cygwin, I get complaints about missing entry points.

What do you recommend as the best way to isolate this?

I tried using "prev" with setup.exe but that didn't make the problem go away.

A simple test case with python access to a trivial function works fine (can supply if anyone wants).
The complex dll that used to work simply doesn't return from dlopen.

I downloaded the 20060522 snapshot with debug symbols to get a backtrace with GDB.
GDB says there is a seg fault and somehow this is preventing any information from reaching dlerror().
Without the dlerror() info, it is hard to figure out what needs to change with the dll.
It appears that some constructors are having trouble.

Let me know if there is some single stepping that could be helpful.
(gdb) bt
#0 0x610b1ff8 in pthread_key_create (key=0x6622f8, destructor=0) at
Known issue already fixed in the Cygwin snapshot and in GDB's CVS. This
is not fatal. Just continue until you stop seeing this complaint.

As noted above, this was tested using snapshot 20060522. Should that snapshot have the fix you mention? If it should, then this problem still exists in that snapshot.
If not, then which one should I test?

The part of the fix that is Cygwin-specific is in the Cygwin snapshot you
have. But, like I said, there's another part of the fix that's only in
GDB's CVS version right now. If you want to be rid of the problem right now,
you need both changes and that means you'll need to grab GDB's source from
CVS and build it. But whether you choose to do this or not should not
inhibit your original investigation. Depending on how many times your
code path takes you through pthread_ket_create(), it may test test your
tolerance level for the current work-around though. ;-)
Thanks for pointing me into the GDB and SIGSEGV discussions.
I didn't see the relationship to the dlopen() problem.

I didn't see discussion of a fix to python which has failing
dlopen() calls presumably because of initializations of mutex objects.
Does python need to do what GDB now does?

Is there a workaround/snapshot in the meantime?

I think if you follow this thread, your questions will be answered.


Larry Hall                    
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
838 Washington Street                   (508) 893-9889 - FAX
Holliston, MA 01746

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