The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 650768c512faba8070bf4cfbb28c95eb5cd203f3 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025062303-unsworn-penpal-7142@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 650768c512faba8070bf4cfbb28c95eb5cd203f3 Mon Sep 17 00:00:00 2001 From: Dev Jain dev.jain@arm.com Date: Tue, 27 May 2025 13:56:33 +0530 Subject: [PATCH] arm64: Restrict pagetable teardown to avoid false warning
Commit 9c006972c3fe ("arm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()") removes the pxd_present() checks because the caller checks pxd_present(). But, in case of vmap_try_huge_pud(), the caller only checks pud_present(); pud_free_pmd_page() recurses on each pmd through pmd_free_pte_page(), wherein the pmd may be none. Thus it is possible to hit a warning in the latter, since pmd_none => !pmd_table(). Thus, add a pmd_present() check in pud_free_pmd_page().
This problem was found by code inspection.
Fixes: 9c006972c3fe ("arm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()") Cc: stable@vger.kernel.org Reported-by: Ryan Roberts ryan.roberts@arm.com Acked-by: David Hildenbrand david@redhat.com Signed-off-by: Dev Jain dev.jain@arm.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Reviewed-by: Anshuman Khandual anshuman.khandual@arm.com Reviewed-by: Ryan Roberts ryan.roberts@arm.com Link: https://lore.kernel.org/r/20250527082633.61073-1-dev.jain@arm.com Signed-off-by: Will Deacon will@kernel.org
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 8fcf59ba39db..00ab1d648db6 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1305,7 +1305,8 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) next = addr; end = addr + PUD_SIZE; do { - pmd_free_pte_page(pmdp, next); + if (pmd_present(pmdp_get(pmdp))) + pmd_free_pte_page(pmdp, next); } while (pmdp++, next += PMD_SIZE, next != end);
pud_clear(pudp);