3.16.7-ckt6 -stable review patch. If anyone has any objections, please let me
know.
------------------
From: Geert Uytterhoeven <geert+rene...@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+rene...@glider.be>
Fixes: e512e001dafa54e5 ("ASoC: simple-card: Fix the reference count of device
nodes")
Signed-off-by: Mark Brown <broo...@kernel.org>
[ luis: backported to 3.16:
- adjusted context
- dropped changes to asoc_simple_card_remove() ]
Signed-off-by: Luis Henriques <luis.henriq...@canonical.com>
---
sound/soc/generic/simple-card.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/sound/soc/generic/simple-card.c b/sound/soc/generic/simple-card.c
index 03a7fdcdf114..517a0ff64303 100644
--- a/sound/soc/generic/simple-card.c
+++ b/sound/soc/generic/simple-card.c
@@ -357,9 +357,8 @@ static int asoc_simple_card_parse_of(struct device_node
*node,
}
/* update the reference count of the devices nodes at end of probe */
-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;
@@ -482,7 +481,7 @@ static int asoc_simple_card_probe(struct platform_device
*pdev)
ret = devm_snd_soc_register_card(&pdev->dev, &priv->snd_card);
err:
- asoc_simple_card_unref(pdev);
+ asoc_simple_card_unref(&priv->snd_card);
return ret;
}
--
2.1.4
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