From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, target-devel Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nicholas Bellinger , Herton Ronaldo Krzesinski Subject: [ 51/86] target: Fix divide by zero bug in fabric_max_sectors for unconfigured devices Date: Tue, 26 Feb 2013 16:07:59 -0800 Message-Id: <20130226235918.195820918@linuxfoundation.org> In-Reply-To: <20130226235912.881663118@linuxfoundation.org> References: <20130226235912.881663118@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicholas Bellinger commit 7a3cf6ca1ab2a2f7161c6dec5a787fc7a5de864e upstream This patch fixes a possible divide by zero bug when the fabric_max_sectors device attribute is written and backend se_device failed to be successfully configured -> enabled. Go ahead and use block_size=512 within se_dev_set_fabric_max_sectors() in the event of a target_configure_device() failure case, as no valid dev->dev_attrib.block_size value will have been setup yet. Signed-off-by: Nicholas Bellinger Cc: Herton Ronaldo Krzesinski Signed-off-by: Greg Kroah-Hartman --- drivers/target/target_core_device.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -1230,6 +1230,8 @@ int se_dev_set_max_sectors(struct se_dev int se_dev_set_fabric_max_sectors(struct se_device *dev, u32 fabric_max_sectors) { + int block_size = dev->se_sub_dev->se_dev_attrib.block_size; + if (atomic_read(&dev->dev_export_obj.obj_access_count)) { pr_err("dev[%p]: Unable to change SE Device" " fabric_max_sectors while dev_export_obj: %d count exists\n", @@ -1267,8 +1269,12 @@ int se_dev_set_fabric_max_sectors(struct /* * Align max_sectors down to PAGE_SIZE to follow transport_allocate_data_tasks() */ + if (!block_size) { + block_size = 512; + pr_warn("Defaulting to 512 for zero block_size\n"); + } fabric_max_sectors = se_dev_align_max_sectors(fabric_max_sectors, - dev->se_sub_dev->se_dev_attrib.block_size); + block_size); dev->se_sub_dev->se_dev_attrib.fabric_max_sectors = fabric_max_sectors; pr_debug("dev[%p]: SE Device max_sectors changed to %u\n",