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 <acour...@nvidia.com>
Cc: Linus Walleij <linus.wall...@linaro.org>
Signed-off-by: Grant Likely <grant.lik...@secretlab.ca>
---
drivers/gpio/gpiolib.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 8ccf68b..807c9d3 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1884,29 +1884,35 @@ 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)
{
+ unsigned long flags;
struct gpio_chip *chip = NULL;
loff_t index = *pos;
- /* REVISIT this isn't locked against gpio_chip removal ... */
-
s->private = "";
+ spin_lock_irqsave(&gpio_lock, flags);
list_for_each_entry(chip, &gpio_chips, list)
- if (index-- == 0)
+ if (index-- == 0) {
+ spin_unlock_irqrestore(&gpio_lock, flags);
return chip;
+ }
+ spin_unlock_irqrestore(&gpio_lock, flags);
return NULL;
}
static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
+ unsigned long flags;
struct gpio_chip *chip = v;
void *ret = NULL;
+ spin_lock_irqsave(&gpio_lock, flags);
if (list_is_last(&chip->list, &gpio_chips))
ret = NULL;
else
ret = list_entry(chip->list.next, struct gpio_chip, list);
+ spin_unlock_irqrestore(&gpio_lock, flags);
s->private = "\n";
++*pos;
--
1.7.10.4
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