write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/mm/page_poison.c
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..
@@ -8,34 +8,16 @@
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 #include <linux/ratelimit.h>
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 #include <linux/kasan.h>
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-static bool want_page_poisoning __read_mostly;
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+bool _page_poisoning_enabled_early;
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+EXPORT_SYMBOL(_page_poisoning_enabled_early);
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+DEFINE_STATIC_KEY_FALSE(_page_poisoning_enabled);
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+EXPORT_SYMBOL(_page_poisoning_enabled);
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 static int __init early_page_poison_param(char *buf)
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 {
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-	if (!buf)
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-		return -EINVAL;
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-	return strtobool(buf, &want_page_poisoning);
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+	return kstrtobool(buf, &_page_poisoning_enabled_early);
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 }
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 early_param("page_poison", early_page_poison_param);
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-
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-/**
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- * page_poisoning_enabled - check if page poisoning is enabled
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- *
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- * Return true if page poisoning is enabled, or false if not.
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- */
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-bool page_poisoning_enabled(void)
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-{
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-	/*
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-	 * Assumes that debug_pagealloc_enabled is set before
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-	 * free_all_bootmem.
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-	 * Page poisoning is debug page alloc for some arches. If
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-	 * either of those options are enabled, enable poisoning.
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-	 */
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-	return (want_page_poisoning ||
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-		(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
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-		debug_pagealloc_enabled()));
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-}
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-EXPORT_SYMBOL_GPL(page_poisoning_enabled);
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 static void poison_page(struct page *page)
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 {
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@@ -43,12 +25,12 @@
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 	/* KASAN still think the page is in-use, so skip it. */
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 	kasan_disable_current();
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-	memset(addr, PAGE_POISON, PAGE_SIZE);
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+	memset(kasan_reset_tag(addr), PAGE_POISON, PAGE_SIZE);
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 	kasan_enable_current();
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 	kunmap_atomic(addr);
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 }
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-static void poison_pages(struct page *page, int n)
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+void __kernel_poison_pages(struct page *page, int n)
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 {
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 	int i;
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@@ -68,9 +50,6 @@
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 	static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
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 	unsigned char *start;
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 	unsigned char *end;
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-
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-	if (IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY))
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-		return;
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 	start = memchr_inv(mem, PAGE_POISON, bytes);
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 	if (!start)
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@@ -98,32 +77,23 @@
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 	void *addr;
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 	addr = kmap_atomic(page);
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+	kasan_disable_current();
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 	/*
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 	 * Page poisoning when enabled poisons each and every page
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 	 * that is freed to buddy. Thus no extra check is done to
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-	 * see if a page was posioned.
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+	 * see if a page was poisoned.
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 	 */
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-	check_poison_mem(addr, PAGE_SIZE);
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+	check_poison_mem(kasan_reset_tag(addr), PAGE_SIZE);
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+	kasan_enable_current();
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 	kunmap_atomic(addr);
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 }
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-static void unpoison_pages(struct page *page, int n)
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+void __kernel_unpoison_pages(struct page *page, int n)
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 {
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 	int i;
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 	for (i = 0; i < n; i++)
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 		unpoison_page(page + i);
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-}
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-
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-void kernel_poison_pages(struct page *page, int numpages, int enable)
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-{
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-	if (!page_poisoning_enabled())
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-		return;
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-
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-	if (enable)
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-		unpoison_pages(page, numpages);
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-	else
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-		poison_pages(page, numpages);
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 }
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 #ifndef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC