Re: [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations

Steven Rostedt
2018-06-06T13:57:18Z

On Wed, 6 Jun 2018 05:21:55 +0800
kbuild test robot <lkp@intel.com> wrote:

> Hi Changbin,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on linus/master]
> [also build test WARNING on v4.17 next-20180605]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/changbin-du-intel-com/kernel-hacking-GCC-optimization-for-better-debug-experience-Og/20180606-001415
> config: ia64-allmodconfig (attached as .config)
> compiler: ia64-linux-gcc (GCC) 8.1.0
> reproduce:
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> make.cross ARCH=ia64
>
> All warnings (new ones prefixed by >>):
>
> drivers//staging/greybus/fw-management.c: In function 'fw_mgmt_load_and_validate_operation':
> >> drivers//staging/greybus/fw-management.c:153:2: warning: 'strncpy' specified bound 10 equals destination size [-Wstringop-truncation]
> strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers//staging/greybus/fw-management.c: In function 'fw_mgmt_backend_fw_update_operation':
> drivers//staging/greybus/fw-management.c:304:2: warning: 'strncpy' specified bound 10 equals destination size [-Wstringop-truncation]
> strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> --
> drivers/auxdisplay/panel.c: In function 'panel_bind_key':
> >> drivers/auxdisplay/panel.c:1509:2: warning: 'strncpy' specified bound 12 equals destination size [-Wstringop-truncation]
> strncpy(key->u.kbd.press_str, press, sizeof(key->u.kbd.press_str));
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/auxdisplay/panel.c:1510:2: warning: 'strncpy' specified bound 12 equals destination size [-Wstringop-truncation]
> strncpy(key->u.kbd.repeat_str, repeat, sizeof(key->u.kbd.repeat_str));
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Nice! This patch actually caused bugs in other areas of the code to be
caught by the build system.

The patch is not wrong. The code that has these warnings are.

-- Steve

>
> vim +/strncpy +153 drivers//staging/greybus/fw-management.c
>
> 013e6653 Viresh Kumar 2016-05-14 138
> 013e6653 Viresh Kumar 2016-05-14 139 static int fw_mgmt_load_and_validate_operation(struct fw_mgmt *fw_mgmt,
> 013e6653 Viresh Kumar 2016-05-14 140 u8 load_method, const char *tag)
> 013e6653 Viresh Kumar 2016-05-14 141 {
> 013e6653 Viresh Kumar 2016-05-14 142 struct gb_fw_mgmt_load_and_validate_fw_request request;
> 013e6653 Viresh Kumar 2016-05-14 143 int ret;
> 013e6653 Viresh Kumar 2016-05-14 144
> 013e6653 Viresh Kumar 2016-05-14 145 if (load_method != GB_FW_LOAD_METHOD_UNIPRO &&
> 013e6653 Viresh Kumar 2016-05-14 146 load_method != GB_FW_LOAD_METHOD_INTERNAL) {
> 013e6653 Viresh Kumar 2016-05-14 147 dev_err(fw_mgmt->parent,
> 013e6653 Viresh Kumar 2016-05-14 148 "invalid load-method (%d)\n", load_method);
> 013e6653 Viresh Kumar 2016-05-14 149 return -EINVAL;
> 013e6653 Viresh Kumar 2016-05-14 150 }
> 013e6653 Viresh Kumar 2016-05-14 151
> 013e6653 Viresh Kumar 2016-05-14 152 request.load_method = load_method;
> b2abeaa1 Viresh Kumar 2016-08-11 @153 strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);
> 013e6653 Viresh Kumar 2016-05-14 154
> 013e6653 Viresh Kumar 2016-05-14 155 /*
> 013e6653 Viresh Kumar 2016-05-14 156 * The firmware-tag should be NULL terminated, otherwise throw error and
> 013e6653 Viresh Kumar 2016-05-14 157 * fail.
> 013e6653 Viresh Kumar 2016-05-14 158 */
> b2abeaa1 Viresh Kumar 2016-08-11 159 if (request.firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
> 013e6653 Viresh Kumar 2016-05-14 160 dev_err(fw_mgmt->parent, "load-and-validate: firmware-tag is not NULL terminated\n");
> 013e6653 Viresh Kumar 2016-05-14 161 return -EINVAL;
> 013e6653 Viresh Kumar 2016-05-14 162 }
> 013e6653 Viresh Kumar 2016-05-14 163
> 013e6653 Viresh Kumar 2016-05-14 164 /* Allocate ids from 1 to 255 (u8-max), 0 is an invalid id */
> 013e6653 Viresh Kumar 2016-05-14 165 ret = ida_simple_get(&fw_mgmt->id_map, 1, 256, GFP_KERNEL);
> 013e6653 Viresh Kumar 2016-05-14 166 if (ret < 0) {
> 013e6653 Viresh Kumar 2016-05-14 167 dev_err(fw_mgmt->parent, "failed to allocate request id (%d)\n",
> 013e6653 Viresh Kumar 2016-05-14 168 ret);
> 013e6653 Viresh Kumar 2016-05-14 169 return ret;
> 013e6653 Viresh Kumar 2016-05-14 170 }
> 013e6653 Viresh Kumar 2016-05-14 171
> 013e6653 Viresh Kumar 2016-05-14 172 fw_mgmt->intf_fw_request_id = ret;
> 04f0e6eb Viresh Kumar 2016-05-14 173 fw_mgmt->intf_fw_loaded = false;
> 013e6653 Viresh Kumar 2016-05-14 174 request.request_id = ret;
> 013e6653 Viresh Kumar 2016-05-14 175
> 013e6653 Viresh Kumar 2016-05-14 176 ret = gb_operation_sync(fw_mgmt->connection,
> 013e6653 Viresh Kumar 2016-05-14 177 GB_FW_MGMT_TYPE_LOAD_AND_VALIDATE_FW, &request,
> 013e6653 Viresh Kumar 2016-05-14 178 sizeof(request), NULL, 0);
> 013e6653 Viresh Kumar 2016-05-14 179 if (ret) {
> 013e6653 Viresh Kumar 2016-05-14 180 ida_simple_remove(&fw_mgmt->id_map,
> 013e6653 Viresh Kumar 2016-05-14 181 fw_mgmt->intf_fw_request_id);
> 013e6653 Viresh Kumar 2016-05-14 182 fw_mgmt->intf_fw_request_id = 0;
> 013e6653 Viresh Kumar 2016-05-14 183 dev_err(fw_mgmt->parent,
> 013e6653 Viresh Kumar 2016-05-14 184 "load and validate firmware request failed (%d)\n",
> 013e6653 Viresh Kumar 2016-05-14 185 ret);
> 013e6653 Viresh Kumar 2016-05-14 186 return ret;
> 013e6653 Viresh Kumar 2016-05-14 187 }
> 013e6653 Viresh Kumar 2016-05-14 188
> 013e6653 Viresh Kumar 2016-05-14 189 return 0;
> 013e6653 Viresh Kumar 2016-05-14 190 }
> 013e6653 Viresh Kumar 2016-05-14 191
>
> :::::: The code at line 153 was first introduced by commit
> :::::: b2abeaa10d5711e7730bb07120dd60ae27d7b930 greybus: firmware: s/_LEN/_SIZE
>
> :::::: TO: Viresh Kumar <viresh.kumar@linaro.org>
> :::::: CC: Greg Kroah-Hartman <gregkh@google.com>
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation