gpio: sim: fix an invalid __free() usage

gpio_sim_make_line_names() returns NULL or ERR_PTR() so we must not use
__free(kfree) on the returned address. Split this function into two, one
that determines the size of the "gpio-line-names" array to allocate and
one that actually sets the names at correct offsets. The allocation and
assignment of the managed pointer happens in between.

Fixes: 3faf89f27aab ("gpio: sim: simplify code with cleanup helpers")
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Closes: https://lore.kernel.org/all/07c32bf1-6c1a-49d9-b97d-f0ae4a2b42ab@p183/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 271db36..44bf170 100644 (file)
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -19,6 +19,7 @@
 #include <linux/irq.h>
 #include <linux/irq_sim.h>
 #include <linux/list.h>
+#include <linux/minmax.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -685,52 +686,32 @@ gpio_sim_device_config_live_show(struct config_item *item, char *page)
        return sprintf(page, "%c\n", live ? '1' : '0');
 }
 
-static char **gpio_sim_make_line_names(struct gpio_sim_bank *bank,
-                                      unsigned int *line_names_size)
+static unsigned int gpio_sim_get_line_names_size(struct gpio_sim_bank *bank)
 {
-       unsigned int max_offset = 0;
-       bool has_line_names = false;
        struct gpio_sim_line *line;
-       char **line_names;
+       unsigned int size = 0;
 
        list_for_each_entry(line, &bank->line_list, siblings) {
-               if (line->offset >= bank->num_lines)
+               if (!line->name || (line->offset >= bank->num_lines))
                        continue;
 
-               if (line->name) {
-                       if (line->offset > max_offset)
-                               max_offset = line->offset;
-
-                       /*
-                        * max_offset can stay at 0 so it's not an indicator
-                        * of whether line names were configured at all.
-                        */
-                       has_line_names = true;
-               }
+               size = max(size, line->offset + 1);
        }
 
-       if (!has_line_names)
-               /*
-                * This is not an error - NULL means, there are no line
-                * names configured.
-                */
-               return NULL;
-
-       *line_names_size = max_offset + 1;
+       return size;
+}
 
-       line_names = kcalloc(*line_names_size, sizeof(*line_names), GFP_KERNEL);
-       if (!line_names)
-               return ERR_PTR(-ENOMEM);
+static void
+gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names)
+{
+       struct gpio_sim_line *line;
 
        list_for_each_entry(line, &bank->line_list, siblings) {
-               if (line->offset >= bank->num_lines)
+               if (!line->name || (line->offset >= bank->num_lines))
                        continue;
 
-               if (line->name && (line->offset <= max_offset))
-                       line_names[line->offset] = line->name;
+               line_names[line->offset] = line->name;
        }
-
-       return line_names;
 }
 
 static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
@@ -834,7 +815,7 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
                          struct fwnode_handle *parent)
 {
        struct property_entry properties[GPIO_SIM_PROP_MAX];
-       unsigned int prop_idx = 0, line_names_size = 0;
+       unsigned int prop_idx = 0, line_names_size;
        char **line_names __free(kfree) = NULL;
 
        memset(properties, 0, sizeof(properties));
@@ -845,14 +826,19 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
                properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label",
                                                               bank->label);
 
-       line_names = gpio_sim_make_line_names(bank, &line_names_size);
-       if (IS_ERR(line_names))
-               return ERR_CAST(line_names);
+       line_names_size = gpio_sim_get_line_names_size(bank);
+       if (line_names_size) {
+               line_names = kcalloc(line_names_size, sizeof(*line_names),
+                                    GFP_KERNEL);
+               if (!line_names)
+                       return ERR_PTR(-ENOMEM);
+
+               gpio_sim_set_line_names(bank, line_names);
 
-       if (line_names)
                properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
                                                "gpio-line-names",
                                                line_names, line_names_size);
+       }
 
        return fwnode_create_software_node(properties, parent);
 }