Mathieu Desnoyers

The vulnerability is related to the `sys membarrier` function in the Linux kernel's `membarrier` component. It can cause a denial of service due to uncontrolled resource consumption. On some systems, `sys membarrier` can be very expensive, leading to overall slowdowns. To prevent this, a lock has been put on the path to serialize accesses and prevent the function from being called at too high a frequency.

The issue allows local users to cause a denial of service, resulting in a system crash, via crafted use of the sendmmsg system call. This is due to an incorrect pointer dereference in the sys sendmsg function in net/socket.c.