[Bug libc/11230] New: memchr overshoots on ia64

["jrnieder at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

memchr can find a location past the end of its buffer:

#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>

int main(int argc, const char * const argv[])
{
    struct stat st;
    lstat(argv[1], &st);

    int fd = open(argv[1], O_RDONLY);
    void *data = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
    void *t = memchr(data, 0, st.st_size);
    printf("ptr: %p, ret: %p, len: 0x%zx\n", data, t, st.st_size);
    return 0;
}

Example output:
| % ./test /etc/passwd
| ptr: 0x2000000000050000, ret: 0x200000000005040e, len: 0x40e

Tested using Debian libc6.1 2.10.2-5, whose memchr.S matches current glibc HEAD. 
Discovered because git diff uses similar code looking for null bytes to detect 
binary files.

Unfortunately, I do not have an ia64 to test this myself.  Still, I thought you 
might want to know.  Please let me know if any other details would be helpful.

See http://bugs.debian.org/563882 for the original report.  Thanks to Bastian 
Blank for the test case.

-- 
           Summary: memchr overshoots on ia64
           Product: glibc
           Version: 2.11
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: hjl dot tools at gmail dot com
        ReportedBy: jrnieder at gmail dot com
                CC: glibc-bugs at sources dot redhat dot com
 GCC build triplet: ia64-unknown-linux-gnu
  GCC host triplet: ia64-unknown-linux-gnu
GCC target triplet: ia64-unknown-linux-gnu


http://sourceware.org/bugzilla/show_bug.cgi?id=11230

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