Overview
About vulnerability
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.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 4.18.0 (+15 more)
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.