Lucene search

K
ubuntucveUbuntu.comUB:CVE-2021-47318
HistoryMay 21, 2024 - 12:00 a.m.

CVE-2021-47318

2024-05-2100:00:00
ubuntu.com
ubuntu.com
1
linux kernel
use-after-free
vulnerability
arch_topology
scale_freq_data
race-free
synchronize_rcu

6.7 Medium

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.1%

In the Linux kernel, the following vulnerability has been resolved:
arch_topology: Avoid use-after-free for scale_freq_data Currently
topology_scale_freq_tick() (which gets called from scheduler_tick()) may
end up using a pointer to “struct scale_freq_data”, which was previously
cleared by topology_clear_scale_freq_source(), as there is no protection in
place here. The users of topology_clear_scale_freq_source() though needs a
guarantee that the previously cleared scale_freq_data isn’t used anymore,
so they can free the related resources. Since topology_scale_freq_tick() is
called from scheduler tick, we don’t want to add locking in there. Use the
RCU update mechanism instead (which is already used by the scheduler’s
utilization update path) to guarantee race free updates here.
synchronize_rcu() makes sure that all RCU critical sections that started
before it is called, will finish before it returns. And so the callers of
topology_clear_scale_freq_source() don’t need to worry about their callback
getting called anymore.

6.7 Medium

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.1%

Related for UB:CVE-2021-47318