The fuzzer tries to open the timer instances as much as possible, and
this may cause a system hiccup easily. We've already introduced the
cap for the max number of available instances for the h/w timers, and
we should put such a limit also to the slave timers, too.
This patch introduces the limit to the multiple opened slave timers.
The upper limit is hard-coded to 1000 for now, which should suffice
for any practical usages up to now.
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
sound/core/timer.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/sound/core/timer.c b/sound/core/timer.c
index 5c9fbf3f4340..219249627cc3 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -74,6 +74,9 @@ static LIST_HEAD(snd_timer_slave_list);
/* lock for slave active lists */
static DEFINE_SPINLOCK(slave_active_lock);
+#define MAX_SLAVE_INSTANCES 1000
+static int num_slaves;
+
static DEFINE_MUTEX(register_mutex);
static int snd_timer_free(struct snd_timer *timer);
@@ -250,6 +253,10 @@ int snd_timer_open(struct snd_timer_instance **ti,
err = -EINVAL;
goto unlock;
}
+ if (num_slaves >= MAX_SLAVE_INSTANCES) {
+ err = -EBUSY;
+ goto unlock;
+ }
timeri = snd_timer_instance_new(owner, NULL);
if (!timeri) {
err = -ENOMEM;
@@ -259,6 +266,7 @@ int snd_timer_open(struct snd_timer_instance **ti,
timeri->slave_id = tid->device;
timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
list_add_tail(&timeri->open_list, &snd_timer_slave_list);
+ num_slaves++;
err = snd_timer_check_slave(timeri);
if (err < 0) {
snd_timer_close_locked(timeri);
@@ -350,6 +358,8 @@ static int snd_timer_close_locked(struct snd_timer_instance *timeri)
}
list_del(&timeri->open_list);
+ if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
+ num_slaves--;
/* force to stop the timer */
snd_timer_stop(timeri);
--
2.16.4
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