Description of problem:

memchr() with long length returns NULL although searched character exists in the searched string.  Problem does not exist in glibc 2.9 or older.  Problem was found because VMware customers are reporting ASSERTs being hit in VMware's code due to unexpected memchr() return value.

Version-Release number of selected component (if applicable):

2.10.1 according to the http://communities.vmware.com/thread/214671.

How reproducible:

Problem is 100% reproducible using code below.

Steps to Reproduce:
  
/* make sure to build this as 64bit binary. Code should report 0x2525b80 0x2525bc9.  On current Fedora (with 2.10.1 glibc) it returns 0x2525b80 (nil). */
#include <sys/mman.h>
#include <stdio.h>
#include <string.h>

void main(void) {
   char* abc;

   abc = mmap(0x00002525000, 16384, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   abc += 0xB80;
   strcpy(abc, "/mnt/data/dan/VMware/Windows XP Professional/Windows XP Professional.vmdk");
   printf("%p %p\n", abc, memchr(abc, 0, -(unsigned long)abc));
}

Actual results:

0x2525b80 (nil)

Expected results:

0x2525b80 0x2525bc9

Additional info:

memchr() behavior above causes vmware to crash, as it expects that memchr(string, 0, -(unsigned long)string) on NUL terminated string returns NULL only if string is not terminated at all.