[041/114] kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc_hook

Commit Message

Andrew Morton March 25, 2022, 1:10 a.m. UTC

From: Andrey Konovalov <[e-mail]>
Subject: kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc_hook

Pull the SetPageSkipKASanPoison() call in post_alloc_hook() out of the big
if clause for better code readability.  This also allows for more
simplifications in the following patches.

Also turn the kasan_has_integrated_init() check into the proper
kasan_hw_tags_enabled() one.  These checks evaluate to the same value, but
logically skipping kasan poisoning has nothing to do with integrated init.

Link: https://lkml.kernel.org/r/72[e-mail]
Signed-off-by: Andrey Konovalov <[e-mail]>
Acked-by: Marco Elver <[e-mail]>
Cc: Alexander Potapenko <[e-mail]>
Cc: Andrey Ryabinin <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Dmitry Vyukov <[e-mail]>
Cc: Evgenii Stepanov <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Peter Collingbourne <[e-mail]>
Cc: Vincenzo Frascino <[e-mail]>
Cc: Will Deacon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/page_alloc.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Patch

--- a/mm/page_alloc.c~kasan-page_alloc-move-setpageskipkasanpoison-in-post_alloc_hook
+++ a/mm/page_alloc.c
@@ -2383,9 +2383,6 @@  inline void post_alloc_hook(struct page
 		init = false;
 	}
 	if (kasan_has_integrated_init()) {
-		if (gfp_flags & __GFP_SKIP_KASAN_POISON)
-			SetPageSkipKASanPoison(page);
-
 		if (!init_tags)
 			kasan_unpoison_pages(page, order, init);
 	} else {
@@ -2394,6 +2391,9 @@  inline void post_alloc_hook(struct page
 		if (init)
 			kernel_init_free_pages(page, 1 << order);
 	}
+	/* Propagate __GFP_SKIP_KASAN_POISON to page flags. */
+	if (kasan_hw_tags_enabled() && (gfp_flags & __GFP_SKIP_KASAN_POISON))
+		SetPageSkipKASanPoison(page);
 
 	set_page_owner(page, order, gfp_flags);
 	page_table_check_alloc(page, order);