[PATCH] arm64: mm: Add PTE_DIRTY back to PAGE_KERNEL* to fix kexec/hibernation

[Will Deacon]

On Fri, 27 Feb 2026 18:53:06 +0000, Catalin Marinas wrote:
> Commit 143937ca51cc ("arm64, mm: avoid always making PTE dirty in
> pte_mkwrite()") changed pte_mkwrite_novma() to only clear PTE_RDONLY
> when PTE_DIRTY is set. This was to allow writable-clean PTEs for swap
> pages that haven't actually been written.
> 
> However, this broke kexec and hibernation for some platforms. Both go
> through trans_pgd_create_copy() -> _copy_pte(), which calls
> pte_mkwrite_novma() to make the temporary linear-map copy fully
> writable. With the updated pte_mkwrite_novma(), read-only kernel pages
> (without PTE_DIRTY) remain read-only in the temporary mapping.
> While such behaviour is fine for user pages where hardware DBM or
> trapping will make them writeable, subsequent in-kernel writes by the
> kexec relocation code will fault.
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64: mm: Add PTE_DIRTY back to PAGE_KERNEL* to fix kexec/hibernation
      https://git.kernel.org/arm64/c/c25c4aa3f79a

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
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