KMSAN assumes shadow and origin pages for every allocated page are
accessible. For pages in vmalloc region those metadata pages reside in
[VMALLOC_END, VMALLOC_META_END), therefore we must sync a bigger memory
region.
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
To: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
---
Change-Id: I0d54855489870ef1180b37fe2120b601da464bf7
---
arch/x86/mm/fault.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index a51df516b87bf..d22e373fa2124 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -331,11 +331,21 @@ static void dump_pagetable(unsigned long address)
void vmalloc_sync_mappings(void)
{
+#ifndef CONFIG_KMSAN
/*
* 64-bit mappings might allocate new p4d/pud pages
* that need to be propagated to all tasks' PGDs.
*/
sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END);
+#else
+ /*
+ * For KMSAN, make sure metadata pages for vmalloc area and modules are
+ * also synced.
+ */
+ sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_META_END);
+ sync_global_pgds(MODULES_SHADOW_START & PGDIR_MASK,
+ MODULES_ORIGIN_END);
+#endif
}
void vmalloc_sync_unmappings(void)
@@ -360,7 +370,17 @@ static noinline int vmalloc_fault(unsigned long address)
pte_t *pte;
/* Make sure we are in vmalloc area: */
+#ifdef CONFIG_KMSAN
+ /*
+ * For KMSAN, make sure metadata pages for vmalloc area and modules are
+ * also synced.
+ */
+ if (!(address >= VMALLOC_START && address < VMALLOC_META_END) &&
+ !(address >= MODULES_SHADOW_START &&
+ address < MODULES_ORIGIN_END))
+#else
if (!(address >= VMALLOC_START && address < VMALLOC_END))
+#endif
return -1;
/*
--
2.25.1.696.g5e7596f4ac-goog
