In the Linux kernel, the following vulnerability has been resolved: fs/proc: dotaskstat: use sig->statslock to gather the threads/children stats locktasksighand() can trigger a hard lockup. If NRCPUS threads call dotaskstat() at the same time and the process has NRTHREADS, it will spin with irqs disabled O(NRCPUS * NRTHREADS) time. Change dotaskstat() to use sig->statslock to gather the statistics outside of ->siglock protected section, in the likely case this code will run lockless.