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[08/15] x86: Physical address comparisons in fill_p*d/pte

Message ID 2c2a71ec844db597f30754dd79faf87c9de0b21f.1738686764.git.maciej.wieczor-retman@intel.com (mailing list archive)
State New
Headers show
Series kasan: x86: arm64: risc-v: KASAN tag-based mode for x86 | expand

Commit Message

Maciej Wieczor-Retman Feb. 4, 2025, 5:33 p.m. UTC 
Calculating page offset returns a pointer without a tag. When comparing
the calculated offset to a tagged page pointer an error is raised
because they are not equal.

Change pointer comparisons to physical address comparisons as to avoid
issues in KASAN that pointer arithmetic would create.

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
---
 arch/x86/mm/init_64.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ff253648706f..bb101412424a 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -251,7 +251,7 @@  static p4d_t *fill_p4d(pgd_t *pgd, unsigned long vaddr)
 	if (pgd_none(*pgd)) {
 		p4d_t *p4d = (p4d_t *)spp_getpage();
 		pgd_populate(&init_mm, pgd, p4d);
-		if (p4d != p4d_offset(pgd, 0))
+		if (__pa(p4d) != __pa(p4d_offset(pgd, 0)))
 			printk(KERN_ERR "PAGETABLE BUG #00! %p <-> %p\n",
 			       p4d, p4d_offset(pgd, 0));
 	}
@@ -263,7 +263,7 @@  static pud_t *fill_pud(p4d_t *p4d, unsigned long vaddr)
 	if (p4d_none(*p4d)) {
 		pud_t *pud = (pud_t *)spp_getpage();
 		p4d_populate(&init_mm, p4d, pud);
-		if (pud != pud_offset(p4d, 0))
+		if (__pa(pud) != __pa(pud_offset(p4d, 0)))
 			printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n",
 			       pud, pud_offset(p4d, 0));
 	}
@@ -275,7 +275,7 @@  static pmd_t *fill_pmd(pud_t *pud, unsigned long vaddr)
 	if (pud_none(*pud)) {
 		pmd_t *pmd = (pmd_t *) spp_getpage();
 		pud_populate(&init_mm, pud, pmd);
-		if (pmd != pmd_offset(pud, 0))
+		if (__pa(pmd) != __pa(pmd_offset(pud, 0)))
 			printk(KERN_ERR "PAGETABLE BUG #02! %p <-> %p\n",
 			       pmd, pmd_offset(pud, 0));
 	}
@@ -287,7 +287,7 @@  static pte_t *fill_pte(pmd_t *pmd, unsigned long vaddr)
 	if (pmd_none(*pmd)) {
 		pte_t *pte = (pte_t *) spp_getpage();
 		pmd_populate_kernel(&init_mm, pmd, pte);
-		if (pte != pte_offset_kernel(pmd, 0))
+		if (__pa(pte) != __pa(pte_offset_kernel(pmd, 0)))
 			printk(KERN_ERR "PAGETABLE BUG #03!\n");
 	}
 	return pte_offset_kernel(pmd, vaddr);