On Fri 24-11-17 10:29:41, Jiri Slaby wrote:
> On 11/24/2017, 10:28 AM, Michal Hocko wrote:
> > I will repost the fixed patch as a reply to this email.
>
> Since 4.4.101 was already released, you should send a bare fix instead
> then :).
Sigh... Greg, could you queue this one up then? I am really sorry about
the screw up. The rest of the backport should be ok.
---
commit 5dfbfb99a64d1554eac7e3074af49e39bd104c35
Author: Michal Hocko <mhocko@xxxxxxxx>
Date: Fri Nov 24 10:34:07 2017 +0100
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@xxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c
index fe1c61f7cf26..3b8f1b83610e 100644
--- a/mm/debug-pagealloc.c
+++ b/mm/debug-pagealloc.c
@@ -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);
}
--
Michal Hocko
SUSE Labs