Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754218AbbLIWxl (ORCPT ); Wed, 9 Dec 2015 17:53:41 -0500 Received: from mail-pa0-f53.google.com ([209.85.220.53]:35411 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753859AbbLIWu4 (ORCPT ); Wed, 9 Dec 2015 17:50:56 -0500 From: Brian Norris To: Shuah Khan , Greg Kroah-Hartman , Ming Lei Cc: Kees Cook , Brian Norris , , , "Luis R. Rodriguez" Subject: [PATCH v2 3/5] test: firmware_class: add asynchronous request trigger Date: Wed, 9 Dec 2015 14:50:27 -0800 Message-Id: <1449701429-121423-3-git-send-email-computersforpeace@gmail.com> X-Mailer: git-send-email 2.6.0.rc2.230.g3dd15c0 In-Reply-To: <1449701429-121423-1-git-send-email-computersforpeace@gmail.com> References: <1449701429-121423-1-git-send-email-computersforpeace@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3580 Lines: 128 We might want to test for bugs like that found in commit f9692b2699bd ("firmware: fix possible use after free on name on asynchronous request"), where the asynchronous request API had race conditions. Let's add a simple file that will launch the async request, then wait until it's complete and report the status. It's not a true async test (we're using a mutex + wait_for_completion(), so we can't get more than one going at the same time), but it does help make sure the basic API is sane, and it can catch some class of bugs. Signed-off-by: Brian Norris Cc: Luis R. Rodriguez --- v2: * use kstrndup() * don't kfree(name) too early! lib/test_firmware.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/lib/test_firmware.c b/lib/test_firmware.c index 690b9c35a274..a3e8ec3fb1c5 100644 --- a/lib/test_firmware.c +++ b/lib/test_firmware.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -80,6 +81,57 @@ out: } static DEVICE_ATTR_WO(trigger_request); +static DECLARE_COMPLETION(async_fw_done); + +static void trigger_async_request_cb(const struct firmware *fw, void *context) +{ + test_firmware = fw; + complete(&async_fw_done); +} + +static ssize_t trigger_async_request_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int rc; + char *name; + + name = kstrndup(buf, count, GFP_KERNEL); + if (!name) + return -ENOSPC; + + pr_info("loading '%s'\n", name); + + mutex_lock(&test_fw_mutex); + release_firmware(test_firmware); + test_firmware = NULL; + rc = request_firmware_nowait(THIS_MODULE, 1, name, dev, GFP_KERNEL, + NULL, trigger_async_request_cb); + if (rc) { + pr_info("async load of '%s' failed: %d\n", name, rc); + kfree(name); + goto out; + } + /* Free 'name' ASAP, to test for race conditions */ + kfree(name); + + wait_for_completion(&async_fw_done); + + if (test_firmware) { + pr_info("loaded: %zu\n", test_firmware->size); + rc = count; + } else { + pr_err("failed to async load firmware\n"); + rc = -ENODEV; + } + +out: + mutex_unlock(&test_fw_mutex); + + return rc; +} +static DEVICE_ATTR_WO(trigger_async_request); + static int __init test_firmware_init(void) { int rc; @@ -96,9 +148,20 @@ static int __init test_firmware_init(void) goto dereg; } + rc = device_create_file(test_fw_misc_device.this_device, + &dev_attr_trigger_async_request); + if (rc) { + pr_err("could not create async sysfs interface: %d\n", rc); + goto remove_file; + } + pr_warn("interface ready\n"); return 0; + +remove_file: + device_remove_file(test_fw_misc_device.this_device, + &dev_attr_trigger_async_request); dereg: misc_deregister(&test_fw_misc_device); return rc; @@ -110,6 +173,8 @@ static void __exit test_firmware_exit(void) { release_firmware(test_firmware); device_remove_file(test_fw_misc_device.this_device, + &dev_attr_trigger_async_request); + device_remove_file(test_fw_misc_device.this_device, &dev_attr_trigger_request); misc_deregister(&test_fw_misc_device); pr_warn("removed interface\n"); -- 2.6.0.rc2.230.g3dd15c0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/