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Vulnerability CVE-2021-47491
Published: 2024-05-22
| Description: |
In the Linux kernel, the following vulnerability has been resolved:
mm: khugepaged: skip huge page collapse for special files
The read-only THP for filesystems will collapse THP for files opened
readonly and mapped with VM_EXEC. The intended usecase is to avoid TLB
misses for large text segments. But it doesn't restrict the file types
so a THP could be collapsed for a non-regular file, for example, block
device, if it is opened readonly and mapped with EXEC permission. This
may cause bugs, like [1] and [2].
This is definitely not the intended usecase, so just collapse THP for
regular files in order to close the attack surface.
[shy828301@gmail.com: fix vm_file check [3]] |
References: |
https://git.kernel.org/stable/c/6d67b2a73b8e3a079c355bab3c1aef7d85a044b8
https://git.kernel.org/stable/c/5fcb6fce74ffa614d964667110cf1a516c48c6d9
https://git.kernel.org/stable/c/a4aeaa06d45e90f9b279f0b09de84bd00006e733
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