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gdb/208: malloc'ed memory from GDB command line cannot be free'd from within program
- To: gdb-gnats at sources dot redhat dot com
- Subject: gdb/208: malloc'ed memory from GDB command line cannot be free'd from within program
- From: zeller at gnu dot org
- Date: 7 Sep 2001 10:39:06 -0000
- Reply-To: zeller at gnu dot org
>Number: 208
>Category: gdb
>Synopsis: malloc'ed memory from GDB command line cannot be free'd from within program
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Fri Sep 07 03:48:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator: Andreas Zeller
>Release: 5.0
>Organization:
>Environment:
i686-pc-linux-gnu
>Description:
Consider the following program, linked dynamically
against GNU libc:
int main() {
void *p = 0;
(*) free(p);
}
If I set a breakpoint at (*), run the program and type
(gdb) print p = malloc(10)
$1 = (void *) 0x400173a0
(gdb) continue
the program crashes within `free':
Program received signal SIGSEGV, Segmentation fault.
0x40096240 in free () from /lib/libc.so.6
The problem can be resolved by linking the program
statically:
(gdb) print p = malloc(10)
$1 = (void *) 0x8099888
(gdb) cont
Continuing.
Program exited normally.
It should be noted that when linked statically, the
command-line invocation of malloc() returns a very different
value. This is weird - normally, the values should roughly
be the same.
>How-To-Repeat:
(See above)
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: