[PATCH v2] staging: zcache: fix possible sleep under lock

From: Seth Jennings <sjenning@linux.vnet.ibm.com>
To: gregkh@suse.de
Cc: ascardo@holoscopio.com, dan.magenheimer@oracle.com,
	sjenning@linux.vnet.ibm.com, rdunlap@xenotime.net,
	devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] staging: zcache: fix possible sleep under lock
Date: Mon, 22 Aug 2011 14:30:38 -0500	[thread overview]
Message-ID: <1314041438-19156-1-git-send-email-sjenning@linux.vnet.ibm.com> (raw)

zcache_new_pool() calls kmalloc() with GFP_KERNEL which has
__GFP_WAIT set.  However, zcache_new_pool() gets called on
a stack that holds the swap_lock spinlock, leading to a
possible sleep-with-lock situation. The lock is obtained
in enable_swap_info().

The patch replaces GFP_KERNEL with GFP_ATOMIC.

v2: replace with GFP_ATOMIC, not GFP_IOFS

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
---
 drivers/staging/zcache/zcache-main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
index 855a5bb..cdf0128 100644
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -1668,7 +1668,7 @@ static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
 	if (cli == NULL)
 		goto out;
 	atomic_inc(&cli->refcount);
-	pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
+	pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
 	if (pool == NULL) {
 		pr_info("zcache: pool creation failed: out of memory\n");
 		goto out;
-- 
1.7.4.1

