[PATCH v3 5/8] mm/x86: Make pud_leaf() only cares about PSE bit

Peter Xu peterx at redhat.com
Tue Jul 16 05:21:39 AEST 2024


An entry should be reported as PUD leaf even if it's PROT_NONE, in which
case PRESENT bit isn't there. I hit bad pud without this when testing dax
1G on zapping a PROT_NONE PUD.

Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Ingo Molnar <mingo at redhat.com>
Cc: Borislav Petkov <bp at alien8.de>
Cc: Dave Hansen <dave.hansen at linux.intel.com>
Cc: x86 at kernel.org
Acked-by: Dave Hansen <dave.hansen at linux.intel.com>
Signed-off-by: Peter Xu <peterx at redhat.com>
---
 arch/x86/include/asm/pgtable.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 65b8e5bb902c..25fc6d809572 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1073,8 +1073,7 @@ static inline pmd_t *pud_pgtable(pud_t pud)
 #define pud_leaf pud_leaf
 static inline bool pud_leaf(pud_t pud)
 {
-	return (pud_val(pud) & (_PAGE_PSE | _PAGE_PRESENT)) ==
-		(_PAGE_PSE | _PAGE_PRESENT);
+	return pud_val(pud) & _PAGE_PSE;
 }
 
 static inline int pud_bad(pud_t pud)
-- 
2.45.0



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