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vulnrichmentLinuxVULNRICHMENT:CVE-2024-44958
HistorySep 04, 2024 - 6:35 p.m.

CVE-2024-44958 sched/smt: Fix unbalance sched_smt_present dec/inc

2024-09-0418:35:56
Linux
github.com
2
linux kernel vulnerability fix
sched/smt
unbalance sched_smt_present
jump label
negative count
stress test
cpu offline failed
fix
incrementing sched_smt_present

AI Score

7.1

Confidence

Low

SSVC

Exploitation

none

Automatable

no

Technical Impact

partial

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

sched/smt: Fix unbalance sched_smt_present dec/inc

I got the following warn report while doing stress test:

jump label: negative count!
WARNING: CPU: 3 PID: 38 at kernel/jump_label.c:263 static_key_slow_try_dec+0x9d/0xb0
Call Trace:
<TASK>
__static_key_slow_dec_cpuslocked+0x16/0x70
sched_cpu_deactivate+0x26e/0x2a0
cpuhp_invoke_callback+0x3ad/0x10d0
cpuhp_thread_fun+0x3f5/0x680
smpboot_thread_fn+0x56d/0x8d0
kthread+0x309/0x400
ret_from_fork+0x41/0x70
ret_from_fork_asm+0x1b/0x30
</TASK>

Because when cpuset_cpu_inactive() fails in sched_cpu_deactivate(),
the cpu offline failed, but sched_smt_present is decremented before
calling sched_cpu_deactivate(), it leads to unbalanced dec/inc, so
fix it by incrementing sched_smt_present in the error path.

AI Score

7.1

Confidence

Low

SSVC

Exploitation

none

Automatable

no

Technical Impact

partial

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