On 5/27/25 13:56, Dev Jain wrote:
Commit 9c006972c3fe 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
This patch is based on 6.15-rc6.
v2->v3:
- Use pmdp_get()
v1->v2:
- Enforce check in caller
arch/arm64/mm/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ea6695d53fb9..5a9bf291c649 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1286,7 +1286,8 @@ 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);pud_clear(pudp);
Agree with Ryan about keeping pmd_present() to be consistent.
Reviewed-by: Anshuman Khandual anshuman.khandual@arm.com