In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix WARN_ON in tracing_buffers_mmap_close
When a process forks, the child process copies the parent's VMAs but the user_mapped reference count is not incremented. As a result, when both the parent and child processes exit, tracing_buffers_mmap_close() is called twice. On the second call, user_mapped is already 0, causing the function to return -ENODEV and triggering a WARN_ON.
Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set. But this is only a hint, and the application can call madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the application does that, it can trigger this issue on fork.
Fix it by incrementing the user_mapped reference count without re-mapping the pages in the VMA's open callback.
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade bpftool6.18-debuginfoUpgrade kernel6.12-libbpf-develUpgrade kernel6.18-debuginfoUpgrade bpftool6.18Upgrade kernel-livepatch-6.18.20-20.229Upgrade kernel6.12-tools-debuginfoUpgrade kernel6.18-debuginfo-common-x86_64Upgrade python3-perf6.18Upgrade kernel-livepatch-6.12.77-99.140Upgrade python3-perf6.12-debuginfoUpgrade kernel6.18-develUpgrade perf6.18Upgrade kernel6.18-libbpf-staticUpgrade kernel6.12-libbpfUpgrade kernel6.12-libbpf-staticUpgrade bpftool6.12Upgrade perf6.12Upgrade python3-perf6.18-debuginfoUpgrade kernel6.12-libbpf-debuginfoUpgrade kernel6.18-tools-debuginfoUpgrade kernel6.18-tools-develUpgrade kernel6.12-headersUpgrade kernel6.18-debuginfo-common-aarch64Upgrade kernel6.12-toolsUpgrade python3-perf6.12Upgrade kernel6.12-debuginfo-common-x86_64Upgrade kernel6.12Upgrade kernel6.18-modules-extra-commonUpgrade kernel6.12-debuginfoUpgrade bpftool6.12-debuginfoUpgrade perf6.18-debuginfoUpgrade kernel6.18-libbpfUpgrade kernel6.18-libbpf-debuginfoUpgrade perf6.12-debuginfoUpgrade kernel6.12-tools-develUpgrade kernel6.18-toolsUpgrade kernel6.12-modules-extraUpgrade kernel6.18-libbpf-develUpgrade kernel6.12-debuginfo-common-aarch64Upgrade kernel6.18-modules-extraUpgrade kernel6.12-modules-extra-commonUpgrade kernel6.18-headersUpgrade kernel6.18Upgrade kernel6.12-devel | Apr 9, 2026 | Mar 25, 2026 |
| Debian | — | Upgrade linux | Jul 23, 2026 | Jul 23, 2026 |
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