Commit 0208fabf authored Nov 24, 2017 by Michal Hocko Committed by Greg Kroah-Hartman Nov 24, 2017

mm, hwpoison: fixup "mm: check the return value of lookup_page_ext for all call sites"




Backport of the upstream commit f86e4271978b ("mm: check the return
value of lookup_page_ext for all call sites") is wrong for hwpoison
pages. I have accidentally negated the condition for bailout. This
basically disables hwpoison pages tracking while the code still
might crash on unusual configurations when struct pages do not have
page_ext allocated. The fix is trivial to invert the condition.

Reported-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 5baf0fb2

mm/debug-pagealloc.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -34,7 +34,7 @@ static inline void set_page_poison(struct page *page)
		struct page_ext *page_ext;

		page_ext = lookup_page_ext(page);
		if (page_ext)
		if (!page_ext)
		return;
		__set_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
		}
		@@ -44,7 +44,7 @@ static inline void clear_page_poison(struct page *page)
		struct page_ext *page_ext;

		page_ext = lookup_page_ext(page);
		if (page_ext)
		if (!page_ext)
		return;
		__clear_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
		}
		@@ -54,7 +54,7 @@ static inline bool page_poison(struct page *page)
		struct page_ext *page_ext;

		page_ext = lookup_page_ext(page);
		if (page_ext)
		if (!page_ext)
		return false;
		return test_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
		}