[alsa-devel] [PATCH] ak4117: Do not free priv until timer handler hasn't actually stopped using it
Function del_timer() does not guarantee that timer was really deleted. If the timer handler is beeing executed at the moment, the function does nothing. So, it's possible to use already freed memory in the handler:
[ref: Documentation/DocBook/kernel-locking.tmpl]
This was found using grep and compile-tested only.
Signed-off-by: Kirill Tkhai ktkhai@parallels.com CC: Jaroslav Kysela perex@perex.cz CC: Takashi Iwai tiwai@suse.de --- sound/i2c/other/ak4117.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/i2c/other/ak4117.c b/sound/i2c/other/ak4117.c index 40e33c9..88452e8 100644 --- a/sound/i2c/other/ak4117.c +++ b/sound/i2c/other/ak4117.c @@ -62,7 +62,7 @@ static void reg_dump(struct ak4117 *ak4117)
static void snd_ak4117_free(struct ak4117 *chip) { - del_timer(&chip->timer); + del_timer_sync(&chip->timer); kfree(chip); }
At Fri, 14 Feb 2014 15:47:57 +0400, Kirill Tkhai wrote:
Function del_timer() does not guarantee that timer was really deleted. If the timer handler is beeing executed at the moment, the function does nothing. So, it's possible to use already freed memory in the handler:
[ref: Documentation/DocBook/kernel-locking.tmpl]
This was found using grep and compile-tested only.
Thanks, applied.
Takashi
Signed-off-by: Kirill Tkhai ktkhai@parallels.com CC: Jaroslav Kysela perex@perex.cz CC: Takashi Iwai tiwai@suse.de
sound/i2c/other/ak4117.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/i2c/other/ak4117.c b/sound/i2c/other/ak4117.c index 40e33c9..88452e8 100644 --- a/sound/i2c/other/ak4117.c +++ b/sound/i2c/other/ak4117.c @@ -62,7 +62,7 @@ static void reg_dump(struct ak4117 *ak4117)
static void snd_ak4117_free(struct ak4117 *chip) {
- del_timer(&chip->timer);
- del_timer_sync(&chip->timer); kfree(chip);
}
participants (2)
-
Kirill Tkhai
-
Takashi Iwai