Commit e9d0ca92 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds

kasan, page_alloc: rework kasan_unpoison_pages call site

Rework the checks around kasan_unpoison_pages() call in post_alloc_hook().

The logical condition for calling this function is:

 - If a software KASAN mode is enabled, we need to mark shadow memory.

 - Otherwise, HW_TAGS KASAN is enabled, and it only makes sense to set
   tags if they haven't already been cleared by tag_clear_highpage(),
   which is indicated by init_tags.

This patch concludes the changes for post_alloc_hook().

Link: https://lkml.kernel.org/r/0ecebd0d7ccd79150e3620ea4185a32d3dfe912f.1643047180.git.andreyknvl@google.comSigned-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Acked-by: default avatarMarco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7e3cbba6
......@@ -2382,16 +2382,21 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
/* Note that memory is already initialized by the loop above. */
init = false;
}
if (kasan_has_integrated_init()) {
if (!init_tags) {
/*
* If either a software KASAN mode is enabled, or,
* in the case of hardware tag-based KASAN,
* if memory tags have not been cleared via tag_clear_highpage().
*/
if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
IS_ENABLED(CONFIG_KASAN_SW_TAGS) ||
kasan_hw_tags_enabled() && !init_tags) {
/* Mark shadow memory or set memory tags. */
kasan_unpoison_pages(page, order, init);
/* Note that memory is already initialized by KASAN. */
if (kasan_has_integrated_init())
init = false;
}
} else {
kasan_unpoison_pages(page, order, init);
}
/* If memory is still not initialized, do it now. */
if (init)
kernel_init_free_pages(page, 1 << order);
......
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