rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access

Summary

In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access In the preparation stage of CPU online, if the corresponding the rdp's->nocb_cb_kthread does not exist, will be created, there is a situation where the rdp's rcuop kthreads creation fails, and then de-offload this CPU's rdp, does not assign this CPU's rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and rdp's->rdp_gp->nocb_gp_kthread is still valid. This will cause the subsequent re-offload operation of this offline CPU, which will pass the conditional check and the kthread_unpark() will access invalid rdp's->nocb_cb_kthread pointer. This commit therefore use rdp's->nocb_gp_kthread instead of rdp_gp's->nocb_gp_kthread for safety check.

Timeline

1. Sep 4, 2025, 3:32 PM UTCCVE published
2. Oct 15, 2026, 1:07 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 3a5761dc025da47960755ac64d9fbf1c32e8cd80 · fixed in b097ae798298885695c339d390b48b4e39619fa7; From 3a5761dc025da47960755ac64d9fbf1c32e8cd80 · fixed in 3da45ec1e485a1a5ad31fe9ddd467c7ee5ae4ef9; From 3a5761dc025da47960755ac64d9fbf1c32e8cd80 · fixed in cce3d027227c69e85896af9fbc6fa9af5c68f067; From 3a5761dc025da47960755ac64d9fbf1c32e8cd80 · fixed in 1c951683a720b17c9ecaad1932bc95b29044611f; From 3a5761dc025da47960755ac64d9fbf1c32e8cd80 · fixed in 9b5ec8e6b31755288a07b3abeeab8cd38e9d3c9d; From 3a5761dc025da47960755ac64d9fbf1c32e8cd80 · fixed in 1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1

• Linux Linux

  6.0

• KernelLinux

  From 6.0.0 · fixed in 6.1.167; From 6.2.0 · fixed in 6.6.130; From 6.7.0 · fixed in 6.12.43; From 6.13.0 · fixed in 6.15.11; From 6.16.0 · fixed in 6.16.2

References 6