UBUNTU-CVE-2025-38704
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.
02 / AFFECTED SOFTWARE
Affected packages
32 explicit affected versions
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37 explicit affected versions
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26 explicit affected versions
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38 explicit affected versions
9 explicit affected versions
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1 explicit affected versions
13 explicit affected versions
43 explicit affected versions
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36 explicit affected versions
14 explicit affected versions
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78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
10 explicit affected versions
30 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1
- https://git.kernel.org/stable/c/1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1
- https://git.kernel.org/stable/c/1c951683a720b17c9ecaad1932bc95b29044611f
- https://git.kernel.org/stable/c/9b5ec8e6b31755288a07b3abeeab8cd38e9d3c9d
- https://git.kernel.org/stable/c/cce3d027227c69e85896af9fbc6fa9af5c68f067
- https://ubuntu.com/security/CVE-2025-38704
- https://ubuntu.com/security/notices/USN-8028-1
- https://ubuntu.com/security/notices/USN-8028-2
- https://ubuntu.com/security/notices/USN-8028-3
- https://ubuntu.com/security/notices/USN-8028-4
- https://ubuntu.com/security/notices/USN-8028-5
- https://ubuntu.com/security/notices/USN-8028-6
- https://ubuntu.com/security/notices/USN-8028-7
- https://ubuntu.com/security/notices/USN-8028-8
- https://ubuntu.com/security/notices/USN-8031-1
- https://ubuntu.com/security/notices/USN-8031-2
- https://ubuntu.com/security/notices/USN-8031-3
- https://ubuntu.com/security/notices/USN-8052-1
- https://ubuntu.com/security/notices/USN-8052-2
- https://ubuntu.com/security/notices/USN-8074-1
- https://ubuntu.com/security/notices/USN-8074-2
- https://ubuntu.com/security/notices/USN-8126-1
- https://www.cve.org/CVERecord?id=CVE-2025-38704