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authorKent Gibson <warthog618@gmail.com>2024-05-10 14:53:42 +0800
committerBartosz Golaszewski <bartosz.golaszewski@linaro.org>2024-05-10 16:38:27 +0200
commitee0166b637a5e376118e9659e5b4148080f1d27e (patch)
treef64fcc73ef03a65eaf151c830743009509cb84fe /drivers/gpio
parent02f6b0e1ec7e0e7d059dddc893645816552039da (diff)
gpiolib: cdev: fix uninitialised kfifo
If a line is requested with debounce, and that results in debouncing in software, and the line is subsequently reconfigured to enable edge detection then the allocation of the kfifo to contain edge events is overlooked. This results in events being written to and read from an uninitialised kfifo. Read events are returned to userspace. Initialise the kfifo in the case where the software debounce is already active. Fixes: 65cff7046406 ("gpiolib: cdev: support setting debounce") Signed-off-by: Kent Gibson <warthog618@gmail.com> Link: https://lore.kernel.org/r/20240510065342.36191-1-warthog618@gmail.com Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/gpiolib-cdev.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 46a45093d4d0..9dad67ea2597 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1193,6 +1193,8 @@ static int edge_detector_update(struct line *line,
struct gpio_v2_line_config *lc,
unsigned int line_idx, u64 edflags)
{
+ u64 eflags;
+ int ret;
u64 active_edflags = READ_ONCE(line->edflags);
unsigned int debounce_period_us =
gpio_v2_line_config_debounce_period(lc, line_idx);
@@ -1204,6 +1206,18 @@ static int edge_detector_update(struct line *line,
/* sw debounced and still will be...*/
if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
line_set_debounce_period(line, debounce_period_us);
+ /*
+ * ensure event fifo is initialised if edge detection
+ * is now enabled.
+ */
+ eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
+ if (eflags && !kfifo_initialized(&line->req->events)) {
+ ret = kfifo_alloc(&line->req->events,
+ line->req->event_buffer_size,
+ GFP_KERNEL);
+ if (ret)
+ return ret;
+ }
return 0;
}