From: andrey.konovalov@linux.dev
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Marco Elver <elver@google.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-arm-kernel@lists.infradead.org,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v6 01/39] kasan, page_alloc: deduplicate should_skip_kasan_poison
Date: Mon, 24 Jan 2022 19:02:09 +0100 [thread overview]
Message-ID: <658b79f5fb305edaf7dc16bc52ea870d3220d4a8.1643047180.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1643047180.git.andreyknvl@google.com>
From: Andrey Konovalov <andreyknvl@google.com>
Currently, should_skip_kasan_poison() has two definitions: one for when
CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, one for when it's not.
Instead of duplicating the checks, add a deferred_pages_enabled()
helper and use it in a single should_skip_kasan_poison() definition.
Also move should_skip_kasan_poison() closer to its caller and clarify
all conditions in the comment.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
Changes v2->v3:
- Update patch description.
---
mm/page_alloc.c | 55 +++++++++++++++++++++++++++++--------------------
1 file changed, 33 insertions(+), 22 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3589febc6d31..25d4f9ad3525 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -378,25 +378,9 @@ int page_group_by_mobility_disabled __read_mostly;
*/
static DEFINE_STATIC_KEY_TRUE(deferred_pages);
-/*
- * Calling kasan_poison_pages() only after deferred memory initialization
- * has completed. Poisoning pages during deferred memory init will greatly
- * lengthen the process and cause problem in large memory systems as the
- * deferred pages initialization is done with interrupt disabled.
- *
- * Assuming that there will be no reference to those newly initialized
- * pages before they are ever allocated, this should have no effect on
- * KASAN memory tracking as the poison will be properly inserted at page
- * allocation time. The only corner case is when pages are allocated by
- * on-demand allocation and then freed again before the deferred pages
- * initialization is done, but this is not likely to happen.
- */
-static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
+static inline bool deferred_pages_enabled(void)
{
- return static_branch_unlikely(&deferred_pages) ||
- (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
- (fpi_flags & FPI_SKIP_KASAN_POISON)) ||
- PageSkipKASanPoison(page);
+ return static_branch_unlikely(&deferred_pages);
}
/* Returns true if the struct page for the pfn is uninitialised */
@@ -447,11 +431,9 @@ defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
return false;
}
#else
-static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
+static inline bool deferred_pages_enabled(void)
{
- return (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
- (fpi_flags & FPI_SKIP_KASAN_POISON)) ||
- PageSkipKASanPoison(page);
+ return false;
}
static inline bool early_page_uninitialised(unsigned long pfn)
@@ -1271,6 +1253,35 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
return ret;
}
+/*
+ * Skip KASAN memory poisoning when either:
+ *
+ * 1. Deferred memory initialization has not yet completed,
+ * see the explanation below.
+ * 2. Skipping poisoning is requested via FPI_SKIP_KASAN_POISON,
+ * see the comment next to it.
+ * 3. Skipping poisoning is requested via __GFP_SKIP_KASAN_POISON,
+ * see the comment next to it.
+ *
+ * Poisoning pages during deferred memory init will greatly lengthen the
+ * process and cause problem in large memory systems as the deferred pages
+ * initialization is done with interrupt disabled.
+ *
+ * Assuming that there will be no reference to those newly initialized
+ * pages before they are ever allocated, this should have no effect on
+ * KASAN memory tracking as the poison will be properly inserted at page
+ * allocation time. The only corner case is when pages are allocated by
+ * on-demand allocation and then freed again before the deferred pages
+ * initialization is done, but this is not likely to happen.
+ */
+static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
+{
+ return deferred_pages_enabled() ||
+ (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
+ (fpi_flags & FPI_SKIP_KASAN_POISON)) ||
+ PageSkipKASanPoison(page);
+}
+
static void kernel_init_free_pages(struct page *page, int numpages, bool zero_tags)
{
int i;
--
2.25.1
next prev parent reply other threads:[~2022-01-24 18:02 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 18:02 [PATCH v6 00/39] kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS andrey.konovalov
2022-01-24 18:02 ` andrey.konovalov [this message]
2022-01-24 18:02 ` [PATCH v6 02/39] kasan, page_alloc: move tag_clear_highpage out of kernel_init_free_pages andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 03/39] kasan, page_alloc: merge kasan_free_pages into free_pages_prepare andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 04/39] kasan, page_alloc: simplify kasan_poison_pages call site andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 05/39] kasan, page_alloc: init memory of skipped pages on free andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 06/39] kasan: drop skip_kasan_poison variable in free_pages_prepare andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 07/39] mm: clarify __GFP_ZEROTAGS comment andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 08/39] kasan: only apply __GFP_ZEROTAGS when memory is zeroed andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 09/39] kasan, page_alloc: refactor init checks in post_alloc_hook andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 10/39] kasan, page_alloc: merge kasan_alloc_pages into post_alloc_hook andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 11/39] kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 12/39] kasan, page_alloc: move SetPageSkipKASanPoison " andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 13/39] kasan, page_alloc: move kernel_init_free_pages " andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 14/39] kasan, page_alloc: rework kasan_unpoison_pages call site andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 15/39] kasan: clean up metadata byte definitions andrey.konovalov
2022-01-24 18:02 ` [PATCH v6 16/39] kasan: define KASAN_VMALLOC_INVALID for SW_TAGS andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 17/39] kasan, x86, arm64, s390: rename functions for modules shadow andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 18/39] kasan, vmalloc: drop outdated VM_KASAN comment andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 19/39] kasan: reorder vmalloc hooks andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 20/39] kasan: add wrappers for " andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 21/39] kasan, vmalloc: reset tags in vmalloc functions andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 22/39] kasan, fork: reset pointer tags of vmapped stacks andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 23/39] kasan, arm64: " andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 24/39] kasan, vmalloc: add vmalloc tagging for SW_TAGS andrey.konovalov
2022-01-24 18:04 ` [PATCH v6 25/39] kasan, vmalloc, arm64: mark vmalloc mappings as pgprot_tagged andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 26/39] kasan, vmalloc: unpoison VM_ALLOC pages after mapping andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 27/39] kasan, mm: only define ___GFP_SKIP_KASAN_POISON with HW_TAGS andrey.konovalov
2022-03-23 11:48 ` Vlastimil Babka
2022-03-23 13:02 ` Sebastian Andrzej Siewior
2022-03-23 13:19 ` Vlastimil Babka
2022-03-23 13:36 ` Andrey Konovalov
2022-03-23 13:57 ` Vlastimil Babka
2022-03-23 15:11 ` Matthew Wilcox
2022-03-25 21:13 ` Andrew Morton
2022-01-24 18:05 ` [PATCH v6 28/39] kasan, page_alloc: allow skipping unpoisoning for HW_TAGS andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 29/39] kasan, page_alloc: allow skipping memory init " andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 30/39] kasan, vmalloc: add vmalloc tagging " andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 31/39] kasan, vmalloc: only tag normal vmalloc allocations andrey.konovalov
2022-03-08 15:17 ` Vasily Gorbik
2022-03-08 15:30 ` Andrey Konovalov
2022-03-08 15:48 ` Vasily Gorbik
2022-01-24 18:05 ` [PATCH v6 32/39] kasan, arm64: don't tag executable " andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 33/39] kasan: mark kasan_arg_stacktrace as __initdata andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 34/39] kasan: clean up feature flags for HW_TAGS mode andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 35/39] kasan: add kasan.vmalloc command line flag andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 36/39] kasan: allow enabling KASAN_VMALLOC and SW/HW_TAGS andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 37/39] arm64: select KASAN_VMALLOC for SW/HW_TAGS modes andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 38/39] kasan: documentation updates andrey.konovalov
2022-01-24 18:05 ` [PATCH v6 39/39] kasan: improve vmalloc tests andrey.konovalov
2022-01-24 18:09 ` [PATCH v6 00/39] kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS Marco Elver
2022-01-24 18:32 ` Andrey Konovalov
2022-04-28 14:13 ` Qian Cai
2022-04-28 15:28 ` Andrey Konovalov
2022-04-28 16:12 ` Qian Cai
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