CVE-2024-26686 fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats

2024-04-0314:54:48

Linux

github.com

linux kernel

fs/proc

task stat

sig->stats_lock

hard lockup

nr_cpus

nr_threads

siglock

statistics

AI Score

6.8

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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.