On Thu, Mar 30, 2006 at 06:49:25PM -0800, Lingyun Li wrote:
> Hi,
>
> I'm on Solaris 10 3/05 using Sun Studio 11 C compiler. I'm using
> ::findleaks to search for memory leaks. I found somehow ::findleaks
> can't find all obvious leaks. I made small a test program below which
> contains three leaks to illustrate the problem. Can anyone tell me
> why? Thanks.
Because pointers to the buffers may still be on the stack. How many
leaks you see will depend on your compiler options, instruction set
architecture, etc.
Cheers,
- jonathan
> test program: leak.c
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
>
> void mysleep()
> {
> printf("sleeping for 60 seconds to allow gcore\n");
> sleep(60);
> }
>
> void *f3()
> {
> return malloc(400);
> }
>
> void f2()
> {
> char *p;
> p=malloc(3330);
> }
>
> void main()
> {
> f2();
> f2();
> f3();
> mysleep();
> }
>
> I compiled it using "cc -g -o leak leak.c". Blow is what did to reproduce the
> problem.
>
> 1) # UMEM_DEBUG=default; LD_PRELAOD=libumem.so.1; export UMEM_DEBUG LD_PRELOAD
> 2) # leak &
> sleeping for 60 seconds to allow gcore
> [1] 23724
> 3) # gcore 23724
> gcore: core.23724 dumped
> 4) # mdb core.23724
> Loading modules: [ libumem.so.1 libc.so.1 ld.so.1 ]
> > ::findleaks -dv
> findleaks: using cached results (-f will force a full run)
> CACHE LEAKED BUFCTL CALLER
> 00033008 1 00043c20 f2+4
> ----------------------------------------------------------------------
> Total 1 buffer, 4096 bytes
>
> umem_alloc_4096 leak: 1 buffer, 4096 bytes
> ADDR BUFADDR TIMESTAMP THREAD
> CACHE LASTLOG CONTENTS
> 43c20 3d200 e8e332cc57f2 1
> 33008 0 0
> libumem.so.1`umem_cache_alloc+0x13c
> libumem.so.1`umem_alloc+0x60
> libumem.so.1`malloc+0x28
> f2+4
> main+0xc
> _start+0x108
>
> >
>
> ::findleaks only found 1 leak but actually there are 3 leaks. Anyone can
> explain why and how to find all leaks? Thank you.
>
> -- Hunter
>
>
> This message posted from opensolaris.org
> _______________________________________________
> mdb-discuss mailing list
> mdb-discuss at opensolaris.org
--
Jonathan Adams, Solaris Kernel Development
