[PATCH v2] zram: fix pool name truncation

From: Sergey Senozhatsky
Date: Tue Aug 11 2015 - 11:44:38 EST

zram_meta_alloc() constructs a pool name for zs_create_pool() call
snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);

However, it defines pool name buffer to be only 8 chars long
(minus trailing zero), which means that we can have only 1000
pool names: zram0 -- zram999.

With CONFIG_ZSMALLOC_STAT enabled an attempt to create a device
zram1000 can fail if device zram100 already exists, because
snprintf() will truncate new pool name to zram100 and pass it
to debugfs_create_dir(), causing:

debugfs dir <zram100> creation failed
zram: Error creating memory pool

... and so on (zram101 - zram1010, etc).

Fix it by increasing pool_name buffer size to 15:
-- zram prefix (length 4)
-- int device_id can use up to 10 chars
-- terminating zero byte

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
drivers/block/zram/zram_drv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index b088ca9..1dec01d 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -502,7 +502,7 @@ static void zram_meta_free(struct zram_meta *meta, u64 disksize)
static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
size_t num_pages;
- char pool_name[8];
+ char pool_name[15];
struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);

if (!meta)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/