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>
diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c
index fe1c61f..3b8f1b8 100644
--- a/mm/debug-pagealloc.c
+++ b/mm/debug-pagealloc.c
@@ -34,7 +34,7 @@
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 @@
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 @@
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);
}