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Re: gdb broken inside emacs (again? still?)


On 09/11/2011 5:32 PM, Ken Brown wrote:
On 11/9/2011 4:44 PM, Ryan Johnson wrote:
Running just `gdb' from emacs allows it to initialize, but
attempts to load a file or indeed perform any command hang until a
double-^C cancels the attempt (reporting "C-c C-cquit"). Ironically,
even `quit' hangs, so you have to use ^D to exit. Debugging anything
within emacs is thus completely impossible at this time.
cgf has already stated that this will be fixed in the next release of gdb; see

http://cygwin.com/ml/cygwin/2011-10/msg00564.html
Hmm. After dwelling longer on the above post chain... I think cgf was only talking about fixing the seg fault. Is this freezing somehow related? I didn't think it was.

P.S. If you're building your own emacs and using a Cygwin snapshot, you'll need to apply my patch to fix the memory allocation problem that we discussed a few months ago. You can get this by using setup.exe to download the source for emacs-23.3-3.
Built, but unfortunately no improvement in behavior by gdb. Is there some possibility those cygwin-specific patches somehow are tied up in this? The last time this came up a home-built emacs worked with gdb-7.3.50-1.

As others have reported, gud-gdb can load and run binaries, but then emacs doesn't sync up its output with source files any more...

BTW, I don't know if this has anything to do with anything, but `strace gdb' from the command prompt or inside emacs reports an infinite stream of seg faults:
25 1231358 [main] gdb 4112 __set_errno: void san::leave():277 val 14
--- Process 4112, exception C0000005 at 6111AE63
71 1231429 [main] gdb 4112 exception::handle: In cygwin_except_handler exc 0xC0000005 at 0x6111AE63 sp 0x149C8F4
67 1231496 [main] gdb 4112 exception::handle: In cygwin_except_handler sig 11 at 0x6111AE63
82 1231578 [main] gdb 4112 exception::handle: In cygwin_except_handler calling 0x0
29 1231607 [main] gdb 4112 __set_errno: void san::leave():277 val 14
--- Process 4112, exception C0000005 at 6111AE63
75 1231682 [main] gdb 4112 exception::handle: In cygwin_except_handler exc 0xC0000005 at 0x6111AE63 sp 0x149C8F4
28 1231710 [main] gdb 4112 exception::handle: In cygwin_except_handler sig 11 at 0x6111AE63
28 1231738 [main] gdb 4112 exception::handle: In cygwin_except_handler calling 0x0

^C kills the program, but attempting to type any other character hangs gdb, strace, and the terminal for good measure.


Is gdb just known-unfriendly to strace?

Ryan


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