General program bugs

• Buffer overflow

• Use After free:

Volatile stack
For example, return a pointer on a stack.

• Memory leak:

mtrace

• Double free

• Free unallocated memory

char* string="abcdef";
free string;

• Heap overflow

p=malloc(strnlen(mystr,MAX_LENGTH)
strncpy(p,mystr,MAX_LENGTH)

use mcheck and mprobe MALLOC_CHECK_

• Race condition

static int count=0;

count++;
(1) Read into register
(2) increase to one
(3) write back the new value into memory

• Deadlock

PTHREAD_MUTEX_ERROR_CHECK

• Compiler optimization

volatile: slow, only option for hardware parameters

memory barrier
asm volatile ("" : : : "memory")
write back all the data from register back to the memory. 

• CPU optimization

hardware memory barrier

• Signal Handler

cannot be blocked using locks

• Tips for troubleshooting

Write to system log /var/log/messages
(bash) logger -p err "test"
syslog()

change syslog level by modify the /etc/syslog.conf


disable assert() using NDEBUG

Function to print backtrace
#include
int backtrace(int **buffer, int size)

POSIX threads trace toolkit

use ar to create static library and ln to create a dynamic library