From: Nick Piggin <nickpiggin@yahoo.com.au>
Date: Mon, 16 Mar 2009 10:00:28 +0000 (+1100)
Subject: slob: fix lockup in slob_free()
X-Git-Tag: v2.6.30-rc1~652^2^3
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=6fb8f424393025674fde7869b59f485d1e352182;p=~emulex%2Finfiniband.git

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>
---

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)) {