In the Linux kernel, the following vulnerability has been resolved:

fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats

lock_task_sighand() can trigger a hard lockup.  If NR_CPUS threads call
do_task_stat() at the same time and the process has NR_THREADS, it will
spin with irqs disabled O(NR_CPUS * NR_THREADS) time.

Change do_task_stat() to use sig->stats_lock to gather the statistics
outside of ->siglock protected section, in the likely case this code will
run lockless.

kernel.org https://git.kernel.org/stable/c/27978243f165b44e342f28f449b91327944ea071 [No types assigned]

kernel.org https://git.kernel.org/stable/c/7601df8031fd67310af891897ef6cc0df4209305 [No types assigned]

kernel.org https://git.kernel.org/stable/c/cf4b8c39b9a0bd81c47afc7ef62914a62dd5ec4d [No types assigned]