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CONFIG_DEBUG_PAGEALLOC is now supported by x86, powerpc, sparc64, and s390. This patch implements it for the rest of the architectures by filling the pages with poison byte patterns after free_pages() and verifying the poison patterns before alloc_pages(). This generic one cannot detect invalid page accesses immediately but invalid read access may cause invalid dereference by poisoned memory and invalid write access can be detected after a long delay. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
31 lines
906 B
C
31 lines
906 B
C
#ifndef LINUX_PAGE_DEBUG_FLAGS_H
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#define LINUX_PAGE_DEBUG_FLAGS_H
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/*
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* page->debug_flags bits:
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*
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* PAGE_DEBUG_FLAG_POISON is set for poisoned pages. This is used to
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* implement generic debug pagealloc feature. The pages are filled with
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* poison patterns and set this flag after free_pages(). The poisoned
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* pages are verified whether the patterns are not corrupted and clear
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* the flag before alloc_pages().
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*/
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enum page_debug_flags {
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PAGE_DEBUG_FLAG_POISON, /* Page is poisoned */
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};
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/*
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* Ensure that CONFIG_WANT_PAGE_DEBUG_FLAGS reliably
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* gets turned off when no debug features are enabling it!
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*/
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#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
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#if !defined(CONFIG_PAGE_POISONING) \
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/* && !defined(CONFIG_PAGE_DEBUG_SOMETHING_ELSE) && ... */
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#error WANT_PAGE_DEBUG_FLAGS is turned on with no debug features!
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#endif
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#endif /* CONFIG_WANT_PAGE_DEBUG_FLAGS */
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#endif /* LINUX_PAGE_DEBUG_FLAGS_H */
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