[Uncc-dev] Fwd: Bug#213472: uncc: usually a segmentation fault

[Robert Millan]

Thanks Tom, I'm forwarding this to upstream.

uncc hackers:
 Tom found uncc segfaulting when attempting to decompile a
 wide number of binaries (uncc'ing /bin/true segfaults for me, for example).

 He's providing a GDB run with backtrace and some useful information. See
 below.

On Tue, Sep 30, 2003 at 09:59:33PM +0000, Tom Goulet wrote:
> On Tue, Sep 30, 2003 at 10:58:46PM +0000, Robert Millan wrote:
> 
> > Please do:
> >  - run
> >  - backtrace
> > And send me a log including the last two. Thanks.
> 
> | (gdb) run
> | Starting program: /usr/src/uncc-0.1.2+20030821/uncc true.dasm
> | 
> | Program received signal SIGSEGV, Segmentation fault.
> | 0x4007f1c4 in fgets () from /lib/libc.so.6
> | (gdb) bt
> | #0  0x4007f1c4 in fgets () from /lib/libc.so.6
> | #1  0x9ffff81c in ?? ()
> | #2  0x00000013 in ?? ()
> | #3  0x0000000a in ?? ()
> | #4  0x00000001 in ?? ()
> | #5  0x4014aa60 in __after_morecore_hook () from /lib/libc.so.6
> | #6  0x40014ed4 in ?? ()
> | #7  0x08052cd8 in ?? ()
> | (gdb)
> 
> I don't know why so many functions are unknown there.  I did build with
> debugging information
> 
> | address@hidden:/usr/src/uncc-0.1.2+20030821# make
> | cc -Wall -ggdb   -c -o uncc.o uncc.c
> | cc -Wall -ggdb   -c -o labels.o labels.c
> | cc -Wall -ggdb   -c -o functions.o functions.c
> | cc -Wall -ggdb   -c -o expressions.o expressions.c
> | cc -Wall -ggdb   -c -o registers.o registers.c
> | cc -Wall -ggdb   -c -o stack.o stack.c
> | cc -Wall -ggdb   -c -o source.o source.c
> | cc -Wall -ggdb   -c -o utils.o utils.c
> | cc   uncc.o labels.o functions.o expressions.o registers.o stack.o source.o 
> utils.o   -o uncc
> | address@hidden:/usr/src/uncc-0.1.2+20030821# file uncc
> | uncc: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for 
> GNU/Linux 2.2.0, dynamically linked (uses shared libs), not stripped
> 
> After some research I found out that calling the <fileno> library call
> on the <file> variable, just above where the <fgets> library call would
> be called, produces a segmentation fault:
> | 0x40085a19 in fileno_unlocked () from /lib/libc.so.6
> 
> I have no idea what's clobbering the <file> object, though.  Debugging it
> seems to be beyond my C skills.
> 
> -- 
> Tom Goulet, address@hidden, D8BAD3BC, http://web.em.ca/~tomg/contact.html

-- 
Robert Millan

"[..] but the delight and pride of Aule is in the deed of making, and in the
thing made, and neither in possession nor in his own mastery; wherefore he
gives and hoards not, and is free from care, passing ever on to some new work."

 -- J.R.R.T, Ainulindale (Silmarillion)