On Tue, 14 Feb 2023 21:09:11 -0800, Peter Collingbourne wrote:
During page migration, the copy_highpage function is used to copy the page data to the target page. If the source page is a userspace page with MTE tags, the KASAN tag of the target page must have the match-all tag in order to avoid tag check faults during subsequent accesses to the page by the kernel. However, the target page may have been allocated in a number of ways, some of which will use the KASAN allocator and will therefore end up setting the KASAN tag to a non-match-all tag. Therefore, update the target page's KASAN tag to match the source page.
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Applied to arm64 (for-next/core), thanks!
[1/1] arm64: Reset KASAN tag in copy_highpage with HW tags only https://git.kernel.org/arm64/c/e74a68468062