From 6fb8f424393025674fde7869b59f485d1e352182 Mon Sep 17 00:00:00 2001
From: Nick Piggin <nickpiggin@yahoo.com.au>
Date: Mon, 16 Mar 2009 21:00:28 +1100
Subject: [PATCH] slob: fix lockup in slob_free()

Don't hold SLOB lock when freeing the page. Reduces lock hold width. See
the following thread for discussion of the bug:

  http://marc.info/?l=linux-kernel&m=123709983214143&w=2

Reported-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---
 mm/slob.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/slob.c b/mm/slob.c
index bf7e8fc3aed..f901653707a 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -393,10 +393,11 @@ static void slob_free(void *block, int size)
 		/* Go directly to page allocator. Do not pass slob allocator */
 		if (slob_page_free(sp))
 			clear_slob_page_free(sp);
+		spin_unlock_irqrestore(&slob_lock, flags);
 		clear_slob_page(sp);
 		free_slob_page(sp);
 		free_page((unsigned long)b);
-		goto out;
+		return;
 	}
 
 	if (!slob_page_free(sp)) {
-- 
2.41.1