From fac880c7d074fdfca874114b5c47b36aa034e4ee Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 5 Sep 2018 17:38:57 +0100 Subject: [PATCH] arm64: fix erroneous warnings in page freeing functions In pmd_free_pte_page() and pud_free_pmd_page() we try to warn if they hit a present non-table entry. In both cases we'll warn for non-present entries, as the VM_WARN_ON() only checks the entry is not a table entry. This has been observed to result in warnings when booting a v4.19-rc2 kernel under qemu. Fix this by bailing out earlier for non-present entries. Fixes: ec28bb9c9b0826d7 ("arm64: Implement page table free interfaces") Signed-off-by: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Signed-off-by: Will Deacon --- arch/arm64/mm/mmu.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 65f86271f02b..8080c9f489c3 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -985,8 +985,9 @@ int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) pmd = READ_ONCE(*pmdp); - /* No-op for empty entry and WARN_ON for valid entry */ - if (!pmd_present(pmd) || !pmd_table(pmd)) { + if (!pmd_present(pmd)) + return 1; + if (!pmd_table(pmd)) { VM_WARN_ON(!pmd_table(pmd)); return 1; } @@ -1007,8 +1008,9 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) pud = READ_ONCE(*pudp); - /* No-op for empty entry and WARN_ON for valid entry */ - if (!pud_present(pud) || !pud_table(pud)) { + if (!pud_present(pud)) + return 1; + if (!pud_table(pud)) { VM_WARN_ON(!pud_table(pud)); return 1; } -- 2.30.2