Re: [bug report] pinctrl: add ZTE ZX pinctrl driver support

[Shawn Guo <shawn.guo@linaro.org>]

Hi Dan,

On Thu, Jun 29, 2017 at 12:51:52PM +0300, Dan Carpenter wrote:
> Hello Shawn Guo,
> 
> The patch cbff0c4d27f4: "pinctrl: add ZTE ZX pinctrl driver support"
> from Apr 24, 2017, leads to the following static checker warning:
> 
> 	drivers/pinctrl/zte/pinctrl-zx.c:338 zx_pinctrl_build_state()
> 	warn: passing devm_ allocated variable to kfree. 'functions'

I tried to see this warning with sparse, but failed.  Can you please
tell how I can reproduced this static check warning?

> 
> drivers/pinctrl/zte/pinctrl-zx.c
>    293  
>    294          /* Build function list from pin mux functions */
>    295          functions = devm_kzalloc(&pdev->dev, info->npins * sizeof(*functions),
>                 ^^^^^^^^^^^^^^^^^^^^^^^^
> 
>    296                                   GFP_KERNEL);
>    297          if (!functions)
>    298                  return -ENOMEM;
>    299  
>    300          nfunctions = 0;
>    301          for (i = 0; i < info->npins; i++) {
>    302                  const struct pinctrl_pin_desc *pindesc = info->pins + i;
>    303                  struct zx_pin_data *data = pindesc->drv_data;
>    304                  struct zx_mux_desc *mux;
>    305  
>    306                  /* Reserved pins do not have a drv_data at all */
>    307                  if (!data)
>    308                          continue;
>    309  
>    310                  /* Loop over all muxes for the pin */
>    311                  mux = data->muxes;
>    312                  while (mux->name) {
>    313                          struct function_desc *func = functions;
>    314  
>    315                          /* Search function list for given mux */
>    316                          while (func->name) {
>    317                                  if (strcmp(mux->name, func->name) == 0) {
>    318                                          /* Function exists */
>    319                                          func->num_group_names++;
>    320                                          break;
>    321                                  }
>    322                                  func++;
>    323                          }
>    324  
>    325                          if (!func->name) {
>    326                                  /* New function */
>    327                                  func->name = mux->name;
>    328                                  func->num_group_names = 1;
>    329                                  radix_tree_insert(&pctldev->pin_function_tree,
>    330                                                    nfunctions++, func);
>    331                          }
>    332  
>    333                          mux++;
>    334                  }
>    335          }
>    336  
>    337          pctldev->num_functions = nfunctions;
>    338          functions = krealloc(functions, nfunctions * sizeof(*functions),
>                                      ^^^^^^^^^
> Not allowed.

So I guess the best fix would be changing devm_kzalloc() above to
kzalloc(), and managing the free procedure on my own, right?

Shawn

> 
>    339                               GFP_KERNEL);
>    340  
>    341          /* Find pin groups for every single function */
>    342          for (i = 0; i < info->npins; i++) {