This is a note to let you know that I've just added the patch titled
mm, hwpoison: fixup "mm: check the return value of lookup_page_ext for all call sites"
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-hwpoison-fixup-mm-check-the-return-value-of-lookup_page_ext-for-all-call-sites.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri Nov 24 11:13:07 CET 2017
Date: Fri, 24 Nov 2017 11:13:07 +0100
To: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm, hwpoison: fixup "mm: check the return value of lookup_page_ext for all call sites"
From: Michal Hocko <mhocko@xxxxxxxx>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/debug-pagealloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/debug-pagealloc.c
+++ b/mm/debug-pagealloc.c
@@ -34,7 +34,7 @@ static inline void set_page_poison(struc
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(str
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 pa
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);
}
Patches currently in stable-queue which might be from gregkh@xxxxxxxxxxxxxxxxxxx are
queue-4.4/mm-hwpoison-fixup-mm-check-the-return-value-of-lookup_page_ext-for-all-call-sites.patch