Description

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

x86/sgx: Fix deadlock in SGX NUMA node search

When the current node doesn't have an EPC section configured by firmware
and all other EPC sections are used up, CPU can get stuck inside the
while loop that looks for an available EPC page from remote nodes
indefinitely, leading to a soft lockup. Note how nid_of_current will
never be equal to nid in that while loop because nid_of_current is not
set in sgx_numa_mask.

Also worth mentioning is that it's perfectly fine for the firmware not
to setup an EPC section on a node. While setting up an EPC section on
each node can enhance performance, it is not a requirement for
functionality.

Rework the loop to start and end on *a* node that has SGX memory. This
avoids the deadlock looking for the current SGX-lacking node to show up
in the loop when it never will.

Classification

CVE ID: CVE-2024-49856

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 7.59% (scored less or equal to compared to others)

EPSS Date: 2025-06-02 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: partial

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2024-49856
https://git.kernel.org/stable/c/40fb64257dab507d86b5f1f2a62f3669ef0c91a8
https://git.kernel.org/stable/c/20c96d0aaabfe361fc2a11c173968dc67feadbbf
https://git.kernel.org/stable/c/fb2d057539eda67ec7cfc369bf587e6518a9b99d
https://git.kernel.org/stable/c/0f89fb4042c08fd143bfc28af08bf6c8a0197eea
https://git.kernel.org/stable/c/8132510c915815e6b537ab937d94ed66893bc7b8
https://git.kernel.org/stable/c/9c936844010466535bd46ea4ce4656ef17653644

Timeline