Solaris libumem why not show memory leak for first dynamic allocation

Question

Say

void main()
{
    void *buff;
    buff = malloc(128);
    buff = malloc(60);
    buff = malloc(30);
    buff = malloc(16);
    free(buff);
    sleep(180);
}

ulib mem in solaris10 show only 60 bytes and 30 bytes as leak , why it not show 128 bytes also leaked?

Answer 1

Three memory leaks are detected by mdb and libumem with your code here:

cat > leak.c <<%
int main() { void *buff; buff = malloc(128); buff = malloc(60); buff = malloc(30); buff = malloc(16); free(buff); sleep(180); }
%
gcc -g leak.c -o leak
pkill leak
UMEM_DEBUG=default UMEM_LOGGING=transaction LD_PRELOAD=libumem.so.1 leak &
sleep 5
rm -f core.leak.*
gcore -o core.leak $(pgrep leak) 
mdb leak core.leak.* <<%
::findleaks -d
%
gcore: core.leak.1815 dumped
CACHE     LEAKED   BUFCTL CALLER
0807f010       1 0808b4b8 main+0x29
0807d810       1 0808d088 main+0x39
0807d010       1 08092cd0 main+0x49
------------------------------------------------------------------------
   Total       3 buffers, 280 bytes

umem_alloc_160 leak: 1 buffer, 160 bytes
            ADDR          BUFADDR        TIMESTAMP           THREAD
                            CACHE          LASTLOG         CONTENTS
         808b4b8          8088f28      1af921ab662                1
                          807f010          806c000                0
                 libumem.so.1`umem_cache_alloc_debug+0x144
                 libumem.so.1`umem_cache_alloc+0x19a
                 libumem.so.1`umem_alloc+0xcd
                 libumem.so.1`malloc+0x2a
                 main+0x29
                 _start+0x83

umem_alloc_80 leak: 1 buffer, 80 bytes
            ADDR          BUFADDR        TIMESTAMP           THREAD
                            CACHE          LASTLOG         CONTENTS
         808d088          808cf68      1af921c11eb                1
                          807d810          806c064                0
                 libumem.so.1`umem_cache_alloc_debug+0x144
                 libumem.so.1`umem_cache_alloc+0x19a
                 libumem.so.1`umem_alloc+0xcd
                 libumem.so.1`malloc+0x2a
                 main+0x39
                 _start+0x83

umem_alloc_40 leak: 1 buffer, 40 bytes
            ADDR          BUFADDR        TIMESTAMP           THREAD
                            CACHE          LASTLOG         CONTENTS
         8092cd0          808efc8      1af921f2bd2                1
                          807d010          806c0c8                0
                 libumem.so.1`umem_cache_alloc_debug+0x144
                 libumem.so.1`umem_cache_alloc+0x19a
                 libumem.so.1`umem_alloc+0xcd
                 libumem.so.1`malloc+0x2a
                 main+0x49
                 _start+0x83