wdiff 0.5 "corrupted double-linked list"

[Matthias Bauer]

UPDATE: Bug fixed by patch, see end of the mail.

Using wdiff 0.5 downloaded from
http://wdiff.progiciels-bpi.ca/showfile.html?mode=archives, "latest
stable version sources",
http://wdiff.progiciels-bpi.ca/archives/wdiff-0.5.tar.gz:

Compiled on:
Linux 2.6.11-1.14_FC3smp #1 SMP Thu Apr 7 19:36:23 EDT 2005 x86_64
x86_64 x86_64 GNU/Linux

(Quad Xeon 3GHz)

Running on the following files:

a:
a b c de fgh i j k lmn opqrs FOO BAR baz
__END__

b:
ac dc de fgh i j k lmn opqrs FOO BAR baz fooRRRR
__END__

like this:

$ wdiff a b

produces:

*** glibc detected *** corrupted double-linked list: 0x0000000000505000 ***
[-a b c-]{+ac dc+} de fgh i j k lmn opqrs FOO BAR baz {+fooRRRR+}Aborted

From gdb:

(gdb) set args a b
(gdb) run
Starting program: /home/moeffju/bin/wdiff a b
Detaching after fork from child process 22365.
*** glibc detected *** corrupted double-linked list: 0x0000000000505000 ***
[-a b c-]{+ac dc+} de fgh i j k lmn opqrs FOO BAR baz {+fooRRRR+}
Program received signal SIGABRT, Aborted.
0x0000003ca3a2e37d in raise () from /lib64/tls/libc.so.6
(gdb) bt
#0  0x0000003ca3a2e37d in raise () from /lib64/tls/libc.so.6
#1  0x0000003ca3a2faae in abort () from /lib64/tls/libc.so.6
#2  0x0000003ca3a62a01 in __libc_message () from /lib64/tls/libc.so.6
#3  0x0000003ca3a686e2 in _int_free () from /lib64/tls/libc.so.6
#4  0x0000003ca3a68916 in free () from /lib64/tls/libc.so.6
#5  0x0000003ca3a59a24 in fclose@@GLIBC_2.2.5 () from /lib64/tls/libc.so.6
#6  0x00000000004021b4 in complete_input_program () at wdiff.c:913
#7  0x0000000000402956 in main (argc=0, argv=0x7ffffffff678) at wdiff.c:1312

Changing MALLOC_CHECK_:

$ MALLOC_CHECK_=0 wdiff a b
Segmentation fault

$ MALLOC_CHECK_=1 wdiff a b
malloc: using debugging hooks
malloc: using debugging hooks
*** glibc detected *** free(): invalid pointer: 0x00000000005054b0 ***
[-a b c-]{+ac dc+} de fgh i j k lmn opqrs FOO BAR baz {+fooRRRR+}

And 2:
$ MALLOC_CHECK_=2 wdiff a b
[-a b c-]{+ac dc+} de fgh i j k lmn opqrs FOO BAR baz {+fooRRRR+}Aborted


I don't know C well enough to make any sense of either the error
messages or valgrind's output (which is huge, too). I hope I have given
enough information to find the bug, if not, please just ask.


UPDATE: I first sent this mail to address@hidden, where 
it bounced. In the meantime, I found a patch at 
http://wdiff.progiciels-bpi.ca/showfile.html?name=ideas/courriel/various&index=1 
which seems to fix the problem (double fclose).


Greetings,
Matthias Bauer