[PATCH] mm: fix KASAN memdec_flags checks for zone/node/section
From: David Hildenbrand (Arm)
Date: Fri Jun 26 2026 - 05:06:39 EST
Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
---
include/asm-generic/memory_model.h | 2 +-
include/linux/mm.h | 23 +++++++++++++++--------
include/linux/mm_inline.h | 4 ++--
include/linux/mmzone.h | 24 ++++++++++++------------
mm/page_alloc.c | 6 +++---
mm/slab.h | 2 +-
mm/sparse.c | 2 +-
7 files changed, 35 insertions(+), 28 deletions(-)
diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index efa6610acbc79..f8404bc7773c2 100644
--- a/include/asm-generic/memory_model.h
+++ b/include/asm-generic/memory_model.h
@@ -53,7 +53,7 @@ static inline int pfn_valid(unsigned long pfn)
*/
#define __page_to_pfn(pg) \
({ const struct page *__pg = (pg); \
- int __sec = memdesc_section(__pg->flags); \
+ int __sec = memdesc_section(&__pg->flags); \
(unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \
})
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 485df9c2dbddb..3111e4a6c9c4c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2286,22 +2286,28 @@ static inline int page_zone_id(struct page *page)
}
#ifdef NODE_NOT_IN_PAGE_FLAGS
-int memdesc_nid(memdesc_flags_t mdf);
+int memdesc_nid(const memdesc_flags_t *mdf);
+#elif defined(CONFIG_NUMA)
+static inline int memdesc_nid(const memdesc_flags_t *mdf)
+{
+ ASSERT_EXCLUSIVE_BITS(mdf->f, NODES_MASK << NODES_PGSHIFT);
+ return (mdf->f >> NODES_PGSHIFT) & NODES_MASK;
+}
#else
-static inline int memdesc_nid(memdesc_flags_t mdf)
+static inline int memdesc_nid(const memdesc_flags_t *mdf)
{
- return (mdf.f >> NODES_PGSHIFT) & NODES_MASK;
+ return 0;
}
#endif
static inline int page_to_nid(const struct page *page)
{
- return memdesc_nid(PF_POISONED_CHECK(page)->flags);
+ return memdesc_nid(&PF_POISONED_CHECK(page)->flags);
}
static inline int folio_nid(const struct folio *folio)
{
- return memdesc_nid(folio->flags);
+ return memdesc_nid(&folio->flags);
}
#ifdef CONFIG_NUMA_BALANCING
@@ -2541,12 +2547,13 @@ static inline void set_page_section(struct page *page, unsigned long section)
page->flags.f |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
}
-static inline unsigned long memdesc_section(memdesc_flags_t mdf)
+static inline unsigned long memdesc_section(const memdesc_flags_t *mdf)
{
- return (mdf.f >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
+ ASSERT_EXCLUSIVE_BITS(mdf->f, SECTIONS_MASK << SECTIONS_PGSHIFT);
+ return (mdf->f >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
}
#else /* !SECTION_IN_PAGE_FLAGS */
-static inline unsigned long memdesc_section(memdesc_flags_t mdf)
+static inline unsigned long memdesc_section(const memdesc_flags_t *mdf)
{
return 0;
}
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index a8430a7ae0544..efcddb9925add 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -650,7 +650,7 @@ static inline bool vma_has_recency(const struct vm_area_struct *vma)
static inline size_t num_pages_contiguous(struct page **pages, size_t nr_pages)
{
struct page *cur_page = pages[0];
- unsigned long section = memdesc_section(cur_page->flags);
+ unsigned long section = memdesc_section(&cur_page->flags);
size_t i;
for (i = 1; i < nr_pages; i++) {
@@ -660,7 +660,7 @@ static inline size_t num_pages_contiguous(struct page **pages, size_t nr_pages)
* In unproblematic kernel configs, page_to_section() == 0 and
* the whole check will get optimized out.
*/
- if (memdesc_section(cur_page->flags) != section)
+ if (memdesc_section(&cur_page->flags) != section)
break;
}
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index ca27121871475..19e709d7a13de 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1272,31 +1272,31 @@ static inline bool zone_is_empty(const struct zone *zone)
#define KASAN_TAG_MASK ((1UL << KASAN_TAG_WIDTH) - 1)
#define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1)
-static inline enum zone_type memdesc_zonenum(memdesc_flags_t flags)
+static inline enum zone_type memdesc_zonenum(const memdesc_flags_t *flags)
{
- ASSERT_EXCLUSIVE_BITS(flags.f, ZONES_MASK << ZONES_PGSHIFT);
- return (flags.f >> ZONES_PGSHIFT) & ZONES_MASK;
+ ASSERT_EXCLUSIVE_BITS(flags->f, ZONES_MASK << ZONES_PGSHIFT);
+ return (flags->f >> ZONES_PGSHIFT) & ZONES_MASK;
}
static inline enum zone_type page_zonenum(const struct page *page)
{
- return memdesc_zonenum(page->flags);
+ return memdesc_zonenum(&page->flags);
}
static inline enum zone_type folio_zonenum(const struct folio *folio)
{
- return memdesc_zonenum(folio->flags);
+ return memdesc_zonenum(&folio->flags);
}
#ifdef CONFIG_ZONE_DEVICE
-static inline bool memdesc_is_zone_device(memdesc_flags_t mdf)
+static inline bool memdesc_is_zone_device(const memdesc_flags_t *mdf)
{
return memdesc_zonenum(mdf) == ZONE_DEVICE;
}
static inline struct dev_pagemap *page_pgmap(const struct page *page)
{
- VM_WARN_ON_ONCE_PAGE(!memdesc_is_zone_device(page->flags), page);
+ VM_WARN_ON_ONCE_PAGE(!memdesc_is_zone_device(&page->flags), page);
return page_folio(page)->pgmap;
}
@@ -1311,9 +1311,9 @@ static inline struct dev_pagemap *page_pgmap(const struct page *page)
static inline bool zone_device_pages_have_same_pgmap(const struct page *a,
const struct page *b)
{
- if (memdesc_is_zone_device(a->flags) != memdesc_is_zone_device(b->flags))
+ if (memdesc_is_zone_device(&a->flags) != memdesc_is_zone_device(&b->flags))
return false;
- if (!memdesc_is_zone_device(a->flags))
+ if (!memdesc_is_zone_device(&a->flags))
return true;
return page_pgmap(a) == page_pgmap(b);
}
@@ -1321,7 +1321,7 @@ static inline bool zone_device_pages_have_same_pgmap(const struct page *a,
extern void memmap_init_zone_device(struct zone *, unsigned long,
unsigned long, struct dev_pagemap *);
#else
-static inline bool memdesc_is_zone_device(memdesc_flags_t mdf)
+static inline bool memdesc_is_zone_device(const memdesc_flags_t *mdf)
{
return false;
}
@@ -1338,12 +1338,12 @@ static inline struct dev_pagemap *page_pgmap(const struct page *page)
static inline bool is_zone_device_page(const struct page *page)
{
- return memdesc_is_zone_device(page->flags);
+ return memdesc_is_zone_device(&page->flags);
}
static inline bool folio_is_zone_device(const struct folio *folio)
{
- return memdesc_is_zone_device(folio->flags);
+ return memdesc_is_zone_device(&folio->flags);
}
static inline bool is_zone_movable_page(const struct page *page)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ee902a468c2f5..020a97ca018e9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6904,15 +6904,15 @@ static void __free_contig_range_common(unsigned long pfn, unsigned long nr_pages
continue;
}
- if (start && memdesc_section(page->flags) != start_sec) {
+ if (start && memdesc_section(&page->flags) != start_sec) {
free_prepared_contig_range(start, i - nr_start);
start = page;
nr_start = i;
- start_sec = memdesc_section(page->flags);
+ start_sec = memdesc_section(&page->flags);
} else if (!start) {
start = page;
nr_start = i;
- start_sec = memdesc_section(page->flags);
+ start_sec = memdesc_section(&page->flags);
}
}
diff --git a/mm/slab.h b/mm/slab.h
index bf2f87acf5e3a..1ae8e6084ba32 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -155,7 +155,7 @@ static inline void *slab_address(const struct slab *slab)
static inline int slab_nid(const struct slab *slab)
{
- return memdesc_nid(slab->flags);
+ return memdesc_nid(&slab->flags);
}
static inline pg_data_t *slab_pgdat(const struct slab *slab)
diff --git a/mm/sparse.c b/mm/sparse.c
index 16ac6df3c89fa..8e38477645131 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -43,7 +43,7 @@ static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
#endif
-int memdesc_nid(memdesc_flags_t mdf)
+int memdesc_nid(const memdesc_flags_t *mdf)
{
return section_to_node_table[memdesc_section(mdf)];
}
--
2.43.0
--
Cheers,
David