The patch below does not apply to the 3.11-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 9ab3b598d2dfbdb0153ffa7e4b1456bbff59a25d Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi <[email protected]> Date: Thu, 12 Feb 2015 15:00:25 -0800 Subject: [PATCH] mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page() A race condition starts to be visible in recent mmotm, where a PG_hwpoison flag is set on a migration source page *before* it's back in buddy page poo= l. This is problematic because no page flag is supposed to be set when freeing (see __free_one_page().) So the user-visible effect of this race is that it could trigger the BUG_ON() when soft-offlining is called. The root cause is that we call lru_add_drain_all() to make sure that the page is in buddy, but that doesn't work because this function just schedule= s a work item and doesn't wait its completion. drain_all_pages() does drainin= g directly, so simply dropping lru_add_drain_all() solves this problem. Fixes: f15bdfa802bf ("mm/memory-failure.c: fix memory leak in successful soft offlining") Signed-off-by: Naoya Horiguchi <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Tony Luck <[email protected]> Cc: Chen Gong <[email protected]> Cc: <[email protected]> [3.11+] Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 1a735fad2a13..d487f8dc6d39 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1647,8 +1647,6 @@ static int __soft_offline_page(struct page *page, int flags) * setting PG_hwpoison. */ if (!is_free_buddy_page(page)) - lru_add_drain_all(); - if (!is_free_buddy_page(page)) drain_all_pages(page_zone(page)); SetPageHWPoison(page); if (!is_free_buddy_page(page)) -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
