| Message ID | 8fdbf86842f4eaf2458ecd23d0844058dbc2c7a2.1612208222.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kasan: optimizations and fixes for HW_TAGS | expand |
On Mon, Feb 01, 2021 at 08:43PM +0100, Andrey Konovalov wrote: > Similarly to kasan_kmalloc(), kasan_kmalloc_large() doesn't need > to unpoison the object as it as already unpoisoned by alloc_pages() > (or by ksize() for krealloc()). > > This patch changes kasan_kmalloc_large() to only poison the redzone. > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> > --- > mm/kasan/common.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 128cb330ca73..a7eb553c8e91 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -494,7 +494,6 @@ EXPORT_SYMBOL(__kasan_kmalloc); > void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, > gfp_t flags) > { > - struct page *page; > unsigned long redzone_start; > unsigned long redzone_end; > > @@ -504,12 +503,23 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, > if (unlikely(ptr == NULL)) > return NULL; > > - page = virt_to_page(ptr); > + /* > + * The object has already been unpoisoned by kasan_alloc_pages() for > + * alloc_pages() or by ksize() for krealloc(). > + */ > + > + /* > + * The redzone has byte-level precision for the generic mode. > + * Partially poison the last object granule to cover the unaligned > + * part of the redzone. > + */ > + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) > + kasan_poison_last_granule(ptr, size); > + > + /* Poison the aligned part of the redzone. */ > redzone_start = round_up((unsigned long)(ptr + size), > KASAN_GRANULE_SIZE); > - redzone_end = (unsigned long)ptr + page_size(page); > - > - kasan_unpoison(ptr, size); > + redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr)); > kasan_poison((void *)redzone_start, redzone_end - redzone_start, > KASAN_PAGE_REDZONE); > > -- > 2.30.0.365.g02bc693789-goog >
diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 128cb330ca73..a7eb553c8e91 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -494,7 +494,6 @@ EXPORT_SYMBOL(__kasan_kmalloc); void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags) { - struct page *page; unsigned long redzone_start; unsigned long redzone_end; @@ -504,12 +503,23 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, if (unlikely(ptr == NULL)) return NULL; - page = virt_to_page(ptr); + /* + * The object has already been unpoisoned by kasan_alloc_pages() for + * alloc_pages() or by ksize() for krealloc(). + */ + + /* + * The redzone has byte-level precision for the generic mode. + * Partially poison the last object granule to cover the unaligned + * part of the redzone. + */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + kasan_poison_last_granule(ptr, size); + + /* Poison the aligned part of the redzone. */ redzone_start = round_up((unsigned long)(ptr + size), KASAN_GRANULE_SIZE); - redzone_end = (unsigned long)ptr + page_size(page); - - kasan_unpoison(ptr, size); + redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr)); kasan_poison((void *)redzone_start, redzone_end - redzone_start, KASAN_PAGE_REDZONE);
Similarly to kasan_kmalloc(), kasan_kmalloc_large() doesn't need to unpoison the object as it as already unpoisoned by alloc_pages() (or by ksize() for krealloc()). This patch changes kasan_kmalloc_large() to only poison the redzone. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- mm/kasan/common.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)