diff options
| author | Matthew Wilcox (Oracle) | 2021-10-04 14:45:56 +0100 |
|---|---|---|
| committer | Vlastimil Babka | 2022-01-06 12:25:51 +0100 |
| commit | 0b3eb091d5759479d44cb793fad2c51ea06bdcec (patch) | |
| tree | 00a317cba0a53dc099678ebb16dcec3a4be41539 /mm/usercopy.c | |
| parent | 7213230af5e1e83ff010b3448260b9d3f95dd036 (diff) | |
mm: Convert check_heap_object() to use struct slab
Ensure that we're not seeing a tail page inside __check_heap_object() by
converting to a slab instead of a page. Take the opportunity to mark
the slab as const since we're not modifying it. Also move the
declaration of __check_heap_object() to mm/slab.h so it's not available
to the wider kernel.
[ vbabka@suse.cz: in check_heap_object() only convert to struct slab for
actual PageSlab pages; use folio as intermediate step instead of page ]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Roman Gushchin <guro@fb.com>
Diffstat (limited to 'mm/usercopy.c')
| -rw-r--r-- | mm/usercopy.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/mm/usercopy.c b/mm/usercopy.c index b3de3c4eefba..d0d268135d96 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -20,6 +20,7 @@ #include <linux/atomic.h> #include <linux/jump_label.h> #include <asm/sections.h> +#include "slab.h" /* * Checks if a given pointer and length is contained by the current @@ -223,7 +224,7 @@ static inline void check_page_span(const void *ptr, unsigned long n, static inline void check_heap_object(const void *ptr, unsigned long n, bool to_user) { - struct page *page; + struct folio *folio; if (!virt_addr_valid(ptr)) return; @@ -231,16 +232,16 @@ static inline void check_heap_object(const void *ptr, unsigned long n, /* * When CONFIG_HIGHMEM=y, kmap_to_page() will give either the * highmem page or fallback to virt_to_page(). The following - * is effectively a highmem-aware virt_to_head_page(). + * is effectively a highmem-aware virt_to_slab(). */ - page = compound_head(kmap_to_page((void *)ptr)); + folio = page_folio(kmap_to_page((void *)ptr)); - if (PageSlab(page)) { + if (folio_test_slab(folio)) { /* Check slab allocator for flags and size. */ - __check_heap_object(ptr, n, page, to_user); + __check_heap_object(ptr, n, folio_slab(folio), to_user); } else { /* Verify object does not incorrectly span multiple pages. */ - check_page_span(ptr, n, page, to_user); + check_page_span(ptr, n, folio_page(folio, 0), to_user); } } |