From ce00e7b8cbba060a230a8fcb9d7bd8b6d8d3162c Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Fri, 14 Aug 2015 15:35:19 -0700 Subject: [PATCH] zram: fix pool name truncation zram_meta_alloc() constructs a pool name for zs_create_pool() call as snprintf(pool_name, sizeof(pool_name), "zram%d", device_id); However, it defines pool name buffer to be only 8 bytes 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 debugfs_create_dir(), causing: debugfs dir creation failed zram: Error creating memory pool ... and so on. Fix it by passing zram->disk->disk_name to zram_meta_alloc() instead of divice_id. We construct zram%d name earlier and keep it as a ->disk_name, no need to snprintf() it again. Signed-off-by: Sergey Senozhatsky Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Change-Id: I4c42cc1134b09f93a824d15e589e66fee28af539 --- drivers/block/zram/zram_drv.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 28343e440f6..5c0cb681cd7 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -374,10 +374,9 @@ static void zram_meta_free(struct zram_meta *meta, u64 disksize) kfree(meta); } -static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize) +static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize) { size_t num_pages; - char pool_name[8]; struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL); if (!meta) @@ -390,7 +389,6 @@ static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize) goto out_error; } - snprintf(pool_name, sizeof(pool_name), "zram%d", device_id); meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM); if (!meta->mem_pool) { pr_err("Error creating memory pool\n"); @@ -838,7 +836,7 @@ static ssize_t disksize_store(struct device *dev, return -EINVAL; disksize = PAGE_ALIGN(disksize); - meta = zram_meta_alloc(zram->disk->first_minor, disksize); + meta = zram_meta_alloc(zram->disk->disk_name, disksize); if (!meta) return -ENOMEM; -- 2.20.1