Re: [Valgrind-developers] valgrind: r6640 - trunk/memcheck

[Julian S. <js...@ac...>]

On Sunday 11 March 2007 14:20, Julian Seward wrote:
> On Sunday 11 March 2007 13:58, Dirk Mueller wrote:
> > On Sunday, 11. March 2007, sv...@va... wrote:
> > > It appears glibc-2.5's getenv() function steps along environment
> > > strings in 16-bit chunks, which can cause false errors
> >
> > Are you sure that they're false?
>
> Well, um, err, not sure.  Good question.

Maybe glibc's getenv is fine and the problem is there are invalid
strings in the environment.  The only way I can reproduce this is to
add (putenv) a non-terminated string containing just '=' and then do
a getenv:

  #include <stdlib.h>
  #include <assert.h>
  #include <stdio.h>

  int main ( void )
  {
    int r;
    char* p;
    p = malloc(1); assert(p);
    p[0] = '=';
    r = putenv(p);
    assert(r == 0);
    p = getenv("XYZZY");
    printf("p = %p\n", p);
    return 0;
  }

gives

==27447== Invalid read of size 2
==27447==    at 0x4E593FD: getenv (in /lib64/libc-2.5.so)
==27447==    by 0x4006A5: main (nullenv.c:14)
==27447==  Address 0x4049030 is 0 bytes inside a block of size 1 alloc'd
==27447==    at 0x4C22A76: malloc (vg_replace_malloc.c:207)
==27447==    by 0x400655: main (nullenv.c:10)

Passing any kind of properly terminated string to putenv makes the error go
away.

So perhaps the environment is constructed wrongly.  The first sign of trouble
in a KDE run is this:

(4) ==27107== Invalid read of size 2
(4) ==27107==    at 0x6DE43FD: getenv (in /lib64/libc-2.5.so)
(4) ==27107==    by 0x4082D7: (within /opt/kde3/bin/kdeinit)
(4) ==27107==    by 0x408CCE: (within /opt/kde3/bin/kdeinit)
(4) ==27107==    by 0x6DCFAE3: (below main) (in /lib64/libc-2.5.so)
(4) ==27107==  Address 0x40708e0 is 0 bytes inside a block of size 1 alloc'd
(4) ==27107==    at 0x4C22A76: malloc (vg_replace_malloc.c:207)
(4) ==27107==    by 0x6E25AB1: strdup (in /lib64/libc-2.5.so)
(4) ==27107==    by 0x404E20: (within /opt/kde3/bin/kdeinit)
(4) ==27107==    by 0x408CBD: (within /opt/kde3/bin/kdeinit)
(4) ==27107==    by 0x6DCFAE3: (below main) (in /lib64/libc-2.5.so)

Are there debuginfo packages available for KDE on SuSE 10.2 so we
can find out who is calling strdup?

J