CVE-2026-90046

Summary

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

mm/page_alloc: don't spin_trylock() in NMI on UP

Patch series "mm/page_alloc: fixes for free_pages_nolock() on RT/UP".

Pre-existing bugs found by Sashiko during review of this other series: https://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/

I have not reproduced these bugs, and I suspect there is no real-world user that is affected by them.

This patch (of 2):

As noted in can_spin_trylock(), using this is unsafe in this context. commit 620b46ed6ae17 ("mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP") fixed this on the alloc side but missed the free side.

Impact: If BPF programs using these features in NMI (probably tracing) are present on non-SMP builds this might crash the kernel and is probably exploitable by local attackers for privilege escalation.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux8c57b687e8331eb80e302a2c528b18b966a9ac7a < 06c76d3c389ff504052f64b1acee44651bd847faaffected
LinuxLinux8c57b687e8331eb80e302a2c528b18b966a9ac7a < 68a069b407303e71db371df85036101e8ff59280affected
LinuxLinux8c57b687e8331eb80e302a2c528b18b966a9ac7a < 3105ae628fb785d48b49256468be4f21a7b3cfc0affected
LinuxLinux6.15affected
LinuxLinux0 < 6.15unaffected
LinuxLinux6.18.51 <= 6.18.*unaffected
LinuxLinux7.2.5 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References