input_led_connect creates an atomic context by spin_lock_irqsave and
calls functions which then perform sleeping operations. For example
GFP_KERNEL allocations in led_classdev_register.
So LOCKDEP complains then like:
------------[ cut here ]------------
WARNING: at kernel/lockdep.c:2469 lockdep_trace_alloc+0xbc/0xd0()
Pid: 1, comm: swapper Not tainted 2.6.34-mm1_64+ #5
Call Trace:
...
[<ffffffff8109359c>] lockdep_trace_alloc+0xbc/0xd0
[<ffffffff810f65b2>] kmem_cache_alloc+0x32/0xf0
[<ffffffff81324826>] device_create_vargs+0x56/0x110
[<ffffffff8132490c>] device_create+0x2c/0x30
[<ffffffff8142068c>] led_classdev_register+0x2c/0xe0
[<ffffffff814213de>] input_led_connect+0x21e/0x2c0
...
Fix this by changing the spinlock to mutex as it is used only in
input_handler->connect and ->disconnect and it is safe to sleep
there.
Signed-off-by: Jiri Slaby <[email protected]>
Cc: Richard Purdie <[email protected]>
---
drivers/leds/leds-input.c | 12 +++++-------
1 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/drivers/leds/leds-input.c b/drivers/leds/leds-input.c
index 93ab5ae..794155a 100644
--- a/drivers/leds/leds-input.c
+++ b/drivers/leds/leds-input.c
@@ -92,7 +92,7 @@ static struct led_trigger input_led_triggers[LED_CNT] = {
DEFINE_INPUT_LED_TRIGGER(LED_CHARGING, "charging"),
};
/* Lock for registration coherency */
-static DEFINE_SPINLOCK(input_led_registered_lock);
+static DEFINE_MUTEX(input_led_registered_lock);
/* Which global LED classes and triggers are registered */
static unsigned long input_led_registered[BITS_TO_LONGS(LED_CNT)];
@@ -159,7 +159,6 @@ static int input_led_connect(struct input_handler *handler,
{
struct input_handle *handle;
int i, error = 0;
- unsigned long flags;
struct led_classdev *leds;
if (!test_bit(EV_LED, dev->keybit))
@@ -187,7 +186,7 @@ static int input_led_connect(struct input_handler *handler,
goto err;
/* lazily register missing global input LEDs */
- spin_lock_irqsave(&input_led_registered_lock, flags);
+ mutex_lock(&input_led_registered_lock);
for (i = 0; i < LED_CNT; i++)
if (input_leds[i].name
&& !test_bit(i, input_led_registered)
@@ -199,7 +198,7 @@ static int input_led_connect(struct input_handler *handler,
else
led_trigger_unregister(&input_led_triggers[i]);
}
- spin_unlock_irqrestore(&input_led_registered_lock, flags);
+ mutex_unlock(&input_led_registered_lock);
/* and register this device's LEDs */
for (i = 0; i < LED_CNT; i++)
@@ -239,7 +238,6 @@ err:
static void input_led_disconnect(struct input_handle *handle)
{
int unregister, i;
- unsigned long flags;
struct led_classdev *leds = handle->private;
for (i = 0; i < LED_CNT; i++)
@@ -249,7 +247,7 @@ static void input_led_disconnect(struct input_handle *handle)
input_unregister_handle(handle);
input_led_delete_handle(handle);
- spin_lock_irqsave(&input_led_registered_lock, flags);
+ mutex_lock(&input_led_registered_lock);
for (i = 0; i < LED_CNT; i++) {
if (!test_bit(i, input_led_registered))
continue;
@@ -268,7 +266,7 @@ static void input_led_disconnect(struct input_handle *handle)
led_trigger_unregister(&input_led_triggers[i]);
clear_bit(i, input_led_registered);
}
- spin_unlock_irqrestore(&input_led_registered_lock, flags);
+ mutex_unlock(&input_led_registered_lock);
}
/* Only handle input devices which have LEDs */
--
1.7.1
Jiri Slaby, le Sat 05 Jun 2010 23:12:22 +0200, a ?crit :
> Fix this by changing the spinlock to mutex as it is used only in
> input_handler->connect and ->disconnect and it is safe to sleep
> there.
Right. in a previous patch it was also used in interrupt context, but
now it should be safe indeed.
Andrew, please fold it into the leds-input patch.
> Signed-off-by: Jiri Slaby <[email protected]>
> Cc: Richard Purdie <[email protected]>
Acked-by: Samuel Thibault <[email protected]>
BTW, please also Cc authors of files when reporting bugs... :)
Samuel
On Sun, 6 Jun 2010 01:45:06 +0200
Samuel Thibault <[email protected]> wrote:
> Jiri Slaby, le Sat 05 Jun 2010 23:12:22 +0200, a __crit :
> > Fix this by changing the spinlock to mutex as it is used only in
> > input_handler->connect and ->disconnect and it is safe to sleep
> > there.
>
> Right. in a previous patch it was also used in interrupt context, but
> now it should be safe indeed.
>
> Andrew, please fold it into the leds-input patch.
hm, I did, nine days ago;
btw, leds-route-kbd-leds-through-the-generic-leds-layer.patch is still
in the "stuck" state coz Alessandro said he'd test it ;)
I think I'll start pestering Richard with it anyway.