diff options
| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2010-10-26 23:22:08 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-27 01:52:11 +0200 |
| commit | 572438f9b52236bd8938b1647cc15e027d27ef55 (patch) | |
| tree | 040d41121c01501a613d5f280b2d9fd6ef562447 | |
| parent | mm/hugetlb.c: add missing spin_lock() to hugetlb_cow() (diff) | |
| download | linux-572438f9b52236bd8938b1647cc15e027d27ef55.tar.xz linux-572438f9b52236bd8938b1647cc15e027d27ef55.zip | |
mm: fix is_mem_section_removable() page_order BUG_ON check
page_order() is called by memory hotplug's user interface to check the
section is removable or not. (is_mem_section_removable())
It calls page_order() withoug holding zone->lock.
So, even if the caller does
if (PageBuddy(page))
ret = page_order(page) ...
The caller may hit BUG_ON().
For fixing this, there are 2 choices.
1. add zone->lock.
2. remove BUG_ON().
is_mem_section_removable() is used for some "advice" and doesn't need to
be 100% accurate. This is_removable() can be called via user program..
We don't want to take this important lock for long by user's request. So,
this patch removes BUG_ON().
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/internal.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/internal.h b/mm/internal.h index 6a697bb97fc5..dedb0aff673f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -62,7 +62,7 @@ extern bool is_free_buddy_page(struct page *page); */ static inline unsigned long page_order(struct page *page) { - VM_BUG_ON(!PageBuddy(page)); + /* PageBuddy() must be checked by the caller */ return page_private(page); } |