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H.J. Lu 2011-03-21 05:42:34 CET
On Intel Core i7, I got
[hjl@gnu-6 997]$ cat saved.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
int main()
{
char *buf, *buf2;
buf = (char*)mmap((void*)0x100000000, 0x2000 * 2,
PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
buf = mmap((char *)buf, 0x2000, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
memset(buf, 'a', 0x2000);
buf[0x1fff] = 0;
buf2 = strdup(buf);
if (strncmp (buf + 3994, buf2 + 2635, 6241) >= 0)
abort ();
return 0;
}
[hjl@gnu-6 997]$ gcc saved.c
[hjl@gnu-6 997]$ ./a.out
Segmentation fault
[hjl@gnu-6 997]$ gdb a.out
GNU gdb (GDB) 7.2.50.20110312-cvs
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /export/home/hjl/bugs/libc/997/a.out...(no debugging
symbols found)...done.
(gdb) r
Starting program: /export/home/hjl/bugs/libc/997/a.out
Program received signal SIGSEGV, Segmentation fault.
0x0000003f7d3214a0 in __strncmp_sse42 () from /lib64/libc.so.6
(gdb)
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
http://rhn.redhat.com/errata/RHBA-2011-0584.html
H.J. Lu 2011-03-21 05:42:34 CET On Intel Core i7, I got [hjl@gnu-6 997]$ cat saved.c #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> int main() { char *buf, *buf2; buf = (char*)mmap((void*)0x100000000, 0x2000 * 2, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); buf = mmap((char *)buf, 0x2000, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); memset(buf, 'a', 0x2000); buf[0x1fff] = 0; buf2 = strdup(buf); if (strncmp (buf + 3994, buf2 + 2635, 6241) >= 0) abort (); return 0; } [hjl@gnu-6 997]$ gcc saved.c [hjl@gnu-6 997]$ ./a.out Segmentation fault [hjl@gnu-6 997]$ gdb a.out GNU gdb (GDB) 7.2.50.20110312-cvs Copyright (C) 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-unknown-linux-gnu". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>... Reading symbols from /export/home/hjl/bugs/libc/997/a.out...(no debugging symbols found)...done. (gdb) r Starting program: /export/home/hjl/bugs/libc/997/a.out Program received signal SIGSEGV, Segmentation fault. 0x0000003f7d3214a0 in __strncmp_sse42 () from /lib64/libc.so.6 (gdb)