linux-kernel - [PATCH] HWPOISON: fix invalid page count in printk output

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Date:	Thu, 22 Oct 2009 08:02:32 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	linux-kernel@...r.kernel.org
Cc:	fengguang.wu@...el.com, Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH] HWPOISON: fix invalid page count in printk output

From: Wu Fengguang <fengguang.wu@...el.com>

The madvise injector already holds a reference when passing in a page
to the memory-failure code. The code corrects for this additional reference
for its checks, but the final printk output didn't. Fix that.

Signed-off-by: Wu Fengguang <fengguang.wu@...el.com>
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
 mm/memory-failure.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e354b9f..dacc641 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -613,13 +613,16 @@ static int page_action(struct page_state *ps, struct page *p,
 			unsigned long pfn, int ref)
 {
 	int result;
+	int count;
 
 	result = ps->action(p, pfn);
 	action_result(pfn, ps->msg, result);
-	if (page_count(p) != 1 + ref)
+
+	count = page_count(p) - 1 - ref;
+	if (count != 0)
 		printk(KERN_ERR
 		       "MCE %#lx: %s page still referenced by %d users\n",
-		       pfn, ps->msg, page_count(p) - 1);
+		       pfn, ps->msg, count);
 
 	/* Could do more checks here if page looks ok */
 	/*
-- 
1.6.0.2

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