crash in

John Carter john.carter@tait.co.nz
Tue Oct 1 22:33:00 GMT 2002


On Tue, 1 Oct 2002, Nir Livni wrote:

> Hi all.
> 
> I am trying to upgrade my project which runs on RH7.0 , to RH7.2
> 
> I installed a fresh RH7.2, and tried to run.
> I got this crash backtrace:
> 
> #0  chunk_alloc (ar_ptr=0x40199620, nb=32776) at malloc.c:3076
> #1  0x400e6b47 in __libc_calloc (n=1, elem_size=32768) at malloc.c:3844
> #2  0x403107c4 in zcalloc (opaque=0x0, items=1, size=32768)

Probably a wild pointer corrupting your heap.

Don't delay, valgrind today...
  http://developer.kde.org/~sewardj/
Valgrind is a GPL'd tool to help you find memory-management problems in 
your programs. When a program is run under Valgrind's supervision, all 
reads and writes of memory are checked, and calls to 
malloc/new/free/delete are intercepted. As a result, Valgrind can detect 
problems such as:

    * Use of uninitialised memory
    * Reading/writing memory after it has been free'd
    * Reading/writing off the end of malloc'd blocks
    * Reading/writing inappropriate areas on the stack
    * Memory leaks -- where pointers to malloc'd blocks are lost forever
    * Passing of uninitialised and/or unaddressible memory to system calls
    * Mismatched use of malloc/new/new [] vs free/delete/delete []
* Some misuses of the POSIX pthreads API

Valgrind tracks each byte of memory in the original program with nine 
status bits, one of which tracks addressibility of that byte, while the 
other eight track the validity of the byte. As a result, it can detect the 
use of single uninitialised bits, and does not report spurious errors on 
bitfield operations.



-- 


John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@tait.co.nz
New Zealand

Good Ideas:
Ruby                 - http://www.ruby-lang-org - The best of perl,python,scheme without the pain.
Valgrind             - http://developer.kde.org/~sewardj/ - memory debugger for x86-GNU/Linux
Free your books      - http://www.bookcrossing.com



More information about the Gcc-help mailing list