From 7ddfdb5c5a5b51bdd2cb749d8341d763b079d520 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 13 Jan 2015 21:03:37 +0100 Subject: ASoC: simple-card: Fix crash in asoc_simple_card_unref() If asoc_simple_card_probe() fails, asoc_simple_card_unref() may be called before dev_set_drvdata(), causing a NULL pointer dereference in asoc_simple_card_unref(): Unable to handle kernel NULL pointer dereference at virtual address 000000d4 ... PC is at asoc_simple_card_unref+0x14/0x48 LR is at asoc_simple_card_probe+0x3d4/0x40c This typically happens because asoc_simple_card_parse_of() returns -EPROBE_DEFER, but other failure modes are possible. devm_snd_soc_register_card()/snd_soc_register_card() may fail either before or after dev_set_drvdata(). Pass a snd_soc_card pointer instead of a platform_device pointer to asoc_simple_card_unref() to fix this. Note that if CONFIG_OF_DYNAMIC=n, of_node_put() is a dummy, and gcc may optimize away the loop over card->dai_link, never actually dereferencing card, and thus avoiding the crash... Signed-off-by: Geert Uytterhoeven Fixes: e512e001dafa54e5 ("ASoC: simple-card: Fix the reference count of device nodes") Signed-off-by: Mark Brown Cc: stable@vger.kernel.org --- sound/soc/generic/simple-card.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'sound') diff --git a/sound/soc/generic/simple-card.c b/sound/soc/generic/simple-card.c index fb9240f..7fe3009 100644 --- a/sound/soc/generic/simple-card.c +++ b/sound/soc/generic/simple-card.c @@ -452,9 +452,8 @@ static int asoc_simple_card_parse_of(struct device_node *node, } /* Decrease the reference count of the device nodes */ -static int asoc_simple_card_unref(struct platform_device *pdev) +static int asoc_simple_card_unref(struct snd_soc_card *card) { - struct snd_soc_card *card = platform_get_drvdata(pdev); struct snd_soc_dai_link *dai_link; int num_links; @@ -556,7 +555,7 @@ static int asoc_simple_card_probe(struct platform_device *pdev) return ret; err: - asoc_simple_card_unref(pdev); + asoc_simple_card_unref(&priv->snd_card); return ret; } @@ -572,7 +571,7 @@ static int asoc_simple_card_remove(struct platform_device *pdev) snd_soc_jack_free_gpios(&simple_card_mic_jack, 1, &simple_card_mic_jack_gpio); - return asoc_simple_card_unref(pdev); + return asoc_simple_card_unref(card); } static const struct of_device_id asoc_simple_of_match[] = { -- cgit v1.1