| From 7ddfdb5c5a5b51bdd2cb749d8341d763b079d520 Mon Sep 17 00:00:00 2001 |
| From: Geert Uytterhoeven <geert+renesas@glider.be> |
| Date: Tue, 13 Jan 2015 21:03:37 +0100 |
| Subject: ASoC: simple-card: Fix crash in asoc_simple_card_unref() |
| |
| From: Geert Uytterhoeven <geert+renesas@glider.be> |
| |
| commit 7ddfdb5c5a5b51bdd2cb749d8341d763b079d520 upstream. |
| |
| 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 <geert+renesas@glider.be> |
| Fixes: e512e001dafa54e5 ("ASoC: simple-card: Fix the reference count of device nodes") |
| Signed-off-by: Mark Brown <broonie@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| sound/soc/generic/simple-card.c | 7 +++---- |
| 1 file changed, 3 insertions(+), 4 deletions(-) |
| |
| --- a/sound/soc/generic/simple-card.c |
| +++ b/sound/soc/generic/simple-card.c |
| @@ -453,9 +453,8 @@ static int asoc_simple_card_parse_of(str |
| } |
| |
| /* 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; |
| struct device_node *np; |
| int num_links; |
| @@ -562,7 +561,7 @@ static int asoc_simple_card_probe(struct |
| return ret; |
| |
| err: |
| - asoc_simple_card_unref(pdev); |
| + asoc_simple_card_unref(&priv->snd_card); |
| return ret; |
| } |
| |
| @@ -578,7 +577,7 @@ static int asoc_simple_card_remove(struc |
| 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[] = { |
