Issue 1544279: Socket module is not thread-safe (original) (raw)

The socket module make a great effort to be thread- safe, but misses one big point - it uses single per-instance buffer to hold resolved sockaddr_xxx structures. Therefore, on SMP system it is possible that several threads calling functions that perform address resolution in parallel will stomp on each other resulting in incorrect or invalid address to be used in each case.

For example, two threads calling sendto() in parallel can result in packets to be sent to incorrect addresses - packets from thread one from time to time will be sent to address requested by thread two and vice versa.

Another, smaller issue is that the call to getnameinfo () is not protected with netdb mutex on systems that don't have thread- safe resolver.

P.S. This is very serious problem for us. For some reason my previous patch submission has been downgraded to bug report and forgotten completely, so that I am re-submitting.