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

[Seth Jennings]

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_IOFS, which is
GFP_KERNEL & ~__GFP_WAIT.

Signed-off-by: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>
---
 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..96ca0ee 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_IOFS);
 	if (pool == NULL) {
 		pr_info("zcache: pool creation failed: out of memory\n");
 		goto out;
-- 
1.7.4.1

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