UBUNTU-CVE-2024-46838
In the Linux kernel, the following vulnerability has been resolved: userfaultfd: don't BUG_ON() if khugepaged yanks our page table Since khugepaged was changed to allow retracting page tables in file mappings without holding the mmap lock, these BUG_ON()s are wrong - get rid of them. We could also remove the preceding "if (unlikely(...))" block, but then we could reach pte_offset_map_lock() with transhuge pages not just for file mappings but also for anonymous mappings - which would probably be fine but I think is not necessarily expected.
02 / AFFECTED SOFTWARE
Affected packages
7 explicit affected versions
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7 explicit affected versions
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13 explicit affected versions
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9 explicit affected versions
14 explicit affected versions
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3 explicit affected versions
16 explicit affected versions
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7 explicit affected versions
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35 explicit affected versions
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13 explicit affected versions
9 explicit affected versions
6 explicit affected versions
12 explicit affected versions
50 explicit affected versions
14 explicit affected versions
12 explicit affected versions
27 explicit affected versions
12 explicit affected versions
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: userfaultfd: don't BUG_ON() if khugepaged yanks our page table Since khugepaged was changed to allow retracting page tables in file mappings without holding the mmap lock, these BUG_ON()s are wrong - get rid of them. We could also remove the preceding "if (unlikely(...))" block, but then we could reach pte_offset_map_lock() with transhuge pages not just for file mappings but also for anonymous mappings - which would probably be fine but I think is not necessarily expected.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/4828d207dc5161dc7ddf9a4f6dcfd80c7dd7d20a
- https://git.kernel.org/stable/c/4828d207dc5161dc7ddf9a4f6dcfd80c7dd7d20a
- https://git.kernel.org/stable/c/4a594acc12d5954cdc71d4450a386748bf3d136a
- https://git.kernel.org/stable/c/db978287e908d48b209e374b00d847b2d785e0a9
- https://ubuntu.com/security/CVE-2024-46838
- https://ubuntu.com/security/notices/USN-7154-1
- https://ubuntu.com/security/notices/USN-7154-2
- https://ubuntu.com/security/notices/USN-7155-1
- https://ubuntu.com/security/notices/USN-7156-1
- https://ubuntu.com/security/notices/USN-7196-1
- https://www.cve.org/CVERecord?id=CVE-2024-46838