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From: Kirill Tkhai <ktkhai@parallels.com>
To: Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>
Cc: tkhai@yandex.ru, alsa-devel@alsa-project.org
Subject: [PATCH] ak4117: Do not free priv until timer handler hasn't actually stopped using it
Date: Fri, 14 Feb 2014 15:47:57 +0400
Message-ID: <1392378477.5384.29.camel@tkhai> (raw)

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);
 }
 

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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-14 11:47 Kirill Tkhai [this message]
2014-02-14 13:17 ` Takashi Iwai

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