From ff604cf6d41f1e05f34762e1d764fe14a0f5f964 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Tue, 11 Dec 2012 16:01:32 -0800 Subject: [PATCH] mm: hwpoison: fix action_result() to print out dirty/clean action_result() fails to print out "dirty" even if an error occurred on a dirty pagecache, because when we check PageDirty in action_result() it was cleared after page isolation even if it's dirty before error handling. This can break some applications that monitor this message, so should be fixed. There are several callers of action_result() except page_action(), but either of them are not for LRU pages but for free pages or kernel pages, so we don't have to consider dirty or not for them. Note that PG_dirty can be set outside page locks as described in commit 6746aff74da2 ("HWPOISON: shmem: call set_page_dirty() with locked page"), so this patch does not completely closes the race window, but just narrows it. Signed-off-by: Naoya Horiguchi Reviewed-by: Andi Kleen Cc: Tony Luck Cc: "Jun'ichi Nomura" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 2c9fc7340b12..108c52fa60f6 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -781,16 +781,16 @@ static struct page_state { { compound, compound, "huge", me_huge_page }, #endif - { sc|dirty, sc|dirty, "swapcache", me_swapcache_dirty }, - { sc|dirty, sc, "swapcache", me_swapcache_clean }, + { sc|dirty, sc|dirty, "dirty swapcache", me_swapcache_dirty }, + { sc|dirty, sc, "clean swapcache", me_swapcache_clean }, - { unevict|dirty, unevict|dirty, "unevictable LRU", me_pagecache_dirty}, - { unevict, unevict, "unevictable LRU", me_pagecache_clean}, + { unevict|dirty, unevict|dirty, "dirty unevictable LRU", me_pagecache_dirty }, + { unevict, unevict, "clean unevictable LRU", me_pagecache_clean }, - { mlock|dirty, mlock|dirty, "mlocked LRU", me_pagecache_dirty }, - { mlock, mlock, "mlocked LRU", me_pagecache_clean }, + { mlock|dirty, mlock|dirty, "dirty mlocked LRU", me_pagecache_dirty }, + { mlock, mlock, "clean mlocked LRU", me_pagecache_clean }, - { lru|dirty, lru|dirty, "LRU", me_pagecache_dirty }, + { lru|dirty, lru|dirty, "dirty LRU", me_pagecache_dirty }, { lru|dirty, lru, "clean LRU", me_pagecache_clean }, /* @@ -812,14 +812,14 @@ static struct page_state { #undef slab #undef reserved +/* + * "Dirty/Clean" indication is not 100% accurate due to the possibility of + * setting PG_dirty outside page lock. See also comment above set_page_dirty(). + */ static void action_result(unsigned long pfn, char *msg, int result) { - struct page *page = pfn_to_page(pfn); - - printk(KERN_ERR "MCE %#lx: %s%s page recovery: %s\n", - pfn, - PageDirty(page) ? "dirty " : "", - msg, action_name[result]); + pr_err("MCE %#lx: %s page recovery: %s\n", + pfn, msg, action_name[result]); } static int page_action(struct page_state *ps, struct page *p,