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gpiolib: Fix locking on gpio debugfs files

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The debugfs files really need to hold the gpiolib spinlock before
accessing the list. Otherwise chip addition/removal will cause an oops.

Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Grant Likely 2013-02-09 09:41:49 +00:00
parent 6c0b4e6c85
commit 362432aed5
1 changed files with 9 additions and 3 deletions
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12
drivers/gpio/gpiolib.c
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@ -2053,29 +2053,35 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos) static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
{ {
unsigned long flags;
struct gpio_chip *chip = NULL; struct gpio_chip *chip = NULL;
loff_t index = *pos; loff_t index = *pos;
/* REVISIT this isn't locked against gpio_chip removal ... */
s->private = ""; s->private = "";
spin_lock_irqsave(&gpio_lock, flags);
list_for_each_entry(chip, &gpio_chips, list) list_for_each_entry(chip, &gpio_chips, list)
if (index-- == 0) if (index-- == 0) {
spin_unlock_irqrestore(&gpio_lock, flags);
return chip; return chip;
}
spin_unlock_irqrestore(&gpio_lock, flags);
return NULL; return NULL;
} }
static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos) static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
{ {
unsigned long flags;
struct gpio_chip *chip = v; struct gpio_chip *chip = v;
void *ret = NULL; void *ret = NULL;
spin_lock_irqsave(&gpio_lock, flags);
if (list_is_last(&chip->list, &gpio_chips)) if (list_is_last(&chip->list, &gpio_chips))
ret = NULL; ret = NULL;
else else
ret = list_entry(chip->list.next, struct gpio_chip, list); ret = list_entry(chip->list.next, struct gpio_chip, list);
spin_unlock_irqrestore(&gpio_lock, flags);
s->private = "\n"; s->private = "\n";
++*pos; ++*pos;