From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754653AbbHLNdX (ORCPT ); Wed, 12 Aug 2015 09:33:23 -0400 Received: from mail-pa0-f41.google.com ([209.85.220.41]:36817 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882AbbHLNdW (ORCPT ); Wed, 12 Aug 2015 09:33:22 -0400 From: Sergey Senozhatsky To: Andrew Morton , Minchan Kim Cc: linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [PATCH v3] zram: fix pool name truncation Date: Wed, 12 Aug 2015 22:32:18 +0900 Message-Id: <1439386338-9164-1-git-send-email-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1439299983-8070-1-git-send-email-sergey.senozhatsky@gmail.com> References: <1439299983-8070-1-git-send-email-sergey.senozhatsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 b088ca9..c87d2f6 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -499,10 +499,9 @@ 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) @@ -515,7 +514,6 @@ 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"); @@ -1033,7 +1031,7 @@ 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; -- 2.5.0