ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT
On PREEMPT_RT kernels, after rt6_get_pcpu_route() returns NULL, the
current task can be preempted. Another task running on the same CPU
may then execute rt6_make_pcpu_route() and successfully install a
pcpu_rt entry. When the first task resumes execution, its cmpxchg()
in rt6_make_pcpu_route() will fail because rt6i_pcpu is no longer
NULL, triggering the BUG_ON(prev). It's easy to reproduce it by adding
mdelay() after rt6_get_pcpu_route().
Using preempt_disable/enable is not appropriate here because
ip6_rt_pcpu_alloc() may sleep.
Fix this by handling the cmpxchg() failure gracefully on PREEMPT_RT:
free our allocation and return the existing pcpu_rt installed by
another task. The BUG_ON is replaced by WARN_ON_ONCE for non-PREEMPT_RT
kernels where such races should not occur.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DSA |
DSA-6126-1 | linux security update |
Ubuntu USN |
USN-8162-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Ubuntu USN |
USN-8177-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8177-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8184-1 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8186-1 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8187-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8204-1 | Linux kernel (Raspberry Pi Real-time) vulnerabilities |
Ubuntu USN |
USN-8265-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Wed, 25 Mar 2026 19:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-617 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:6.12:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:* |
|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Thu, 15 Jan 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Tue, 13 Jan 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT On PREEMPT_RT kernels, after rt6_get_pcpu_route() returns NULL, the current task can be preempted. Another task running on the same CPU may then execute rt6_make_pcpu_route() and successfully install a pcpu_rt entry. When the first task resumes execution, its cmpxchg() in rt6_make_pcpu_route() will fail because rt6i_pcpu is no longer NULL, triggering the BUG_ON(prev). It's easy to reproduce it by adding mdelay() after rt6_get_pcpu_route(). Using preempt_disable/enable is not appropriate here because ip6_rt_pcpu_alloc() may sleep. Fix this by handling the cmpxchg() failure gracefully on PREEMPT_RT: free our allocation and return the existing pcpu_rt installed by another task. The BUG_ON is replaced by WARN_ON_ONCE for non-PREEMPT_RT kernels where such races should not occur. | |
| Title | ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:54:21.125Z
Reserved: 2026-01-13T15:30:19.648Z
Link: CVE-2025-71080
No data.
Status : Analyzed
Published: 2026-01-13T16:16:07.550
Modified: 2026-03-25T19:42:22.610
Link: CVE-2025-71080
OpenCVE Enrichment
No data.
Debian DSA
Ubuntu USN