On Wed, Apr 15, 2020 at 09:28:18AM -0700, Scott Branden wrote:

Hi Kees,

On 2020-04-14 8:10 p.m., Kees Cook wrote:

...

On Tue, Apr 14, 2020 at 05:25:17PM -0700, Scott Branden wrote:

...

Remove unnecessary use of test_fw_mutex in test_dev_config_show_xxx functions that show simple bool, int, and u8.

I would expect at least a READ_ONCE(), yes?

I don't understand why you need a READ_ONCE when removing a mutex around an assignment of a parameter passed into a function being assigned to a local variable.

Could you please explain your expectations.

Oops, yes, you're right. I misread and was thinking this was reading from a global. This looks fine.

Reviewed-by: Kees Cook keescook@chromium.org

-Kees

...

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Signed-off-by: Scott Branden scott.branden@broadcom.com

lib/test_firmware.c | 26 +++----------------------- 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/lib/test_firmware.c b/lib/test_firmware.c index 0c7fbcf07ac5..9fee2b93a8d1 100644 --- a/lib/test_firmware.c +++ b/lib/test_firmware.c @@ -310,27 +310,13 @@ static int test_dev_config_update_bool(const char *buf, size_t size, return ret; } -static ssize_t -test_dev_config_show_bool(char *buf,

• 	  bool config)
  

+static ssize_t test_dev_config_show_bool(char *buf, bool val) {

• bool val;
• mutex_lock(&test_fw_mutex);
• val = config;
• mutex_unlock(&test_fw_mutex);
• return snprintf(buf, PAGE_SIZE, "%d\n", val); }

-static ssize_t test_dev_config_show_int(char *buf, int cfg) +static ssize_t test_dev_config_show_int(char *buf, int val) {

• int val;
• mutex_lock(&test_fw_mutex);
• val = cfg;
• mutex_unlock(&test_fw_mutex);
• return snprintf(buf, PAGE_SIZE, "%d\n", val); }

@@ -354,14 +340,8 @@ static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg) return size; } -static ssize_t test_dev_config_show_u8(char *buf, u8 cfg) +static ssize_t test_dev_config_show_u8(char *buf, u8 val) {

• u8 val;
• mutex_lock(&test_fw_mutex);
• val = cfg;
• mutex_unlock(&test_fw_mutex);
• return snprintf(buf, PAGE_SIZE, "%u\n", val); }

-- 2.17.1