Shawn Wang

Name of the Vulnerable Software and Affected Versions: Linux kernel (affected versions not specified) Description: A null pointer dereference error was found in the task numa work() function of the Linux kernel. This issue can occur when running the stress-ng-vm-segv test, which tries to cause a SIGSEGV error on return from unmapping the whole address space of the child process. Normally, this program will not cause kernel crashes, but before the munmap system call returns to user mode, a potential task numa work() for numa balancing could be added and executed. In this scenario, since the child process has no vma after munmap, the vma next() in task numa work() will return a null pointer even if the vma iterator restarts from 0. The issue is resolved by rechecking the vma pointer before dereferencing it in task numa work(). Recommendations: At the moment, there is no information about a newer version that contains a fix for this vulnerability.