Le 23/06/2021 à 11:46, Dan Carpenter a écrit :
On Wed, Jun 23, 2021 at 07:22:45AM +0200, Christophe JAILLET wrote:
If 'of_clk_add_hw_provider()' fails, the previous 'for' loop will have
run completely and 'i' is know to be 'DA7219_DAI_NUM_CLKS'.
In such a case, there will be an out-of-bounds access when using
'da7219->dai_clks_lookup[i]' and '&da7219->dai_clks_hw[i]'.
To avoid that, add a new label, 'err_free_all', which set the expected
value of 'i' in such a case.
Fixes: 78013a1cf297 ("ASoC: da7219: Fix clock handling around codec level probe")
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
sound/soc/codecs/da7219.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
index 13009d08b09a..1e8b491d1fd3 100644
--- a/sound/soc/codecs/da7219.c
+++ b/sound/soc/codecs/da7219.c
@@ -2204,12 +2204,14 @@ static int da7219_register_dai_clks(struct snd_soc_component *component)
da7219->clk_hw_data);
if (ret) {
dev_err(dev, "Failed to register clock provider\n");
- goto err;
+ goto err_free_all;
}
}
return 0;
+err_free_all:
+ i = DA7219_DAI_NUM_CLKS - 1;
err:
do {
if (da7219->dai_clks_lookup[i])
This do while statement is wrong and it leads to potentially calling
clk_hw_unregister() on clks that haven't been registered.
Obviously right.
Thanks for the review Dan.
I'll send a v2 in the coming days.
CJ
I think that calling clk_hw_unregister() on unregistered clocks is
supposed to okay but I found a case where it leads to a WARN_ON()
(Nothing else harmful). It's in __clk_register() if the alloc_clk()
fails:
hw->clk = alloc_clk(core, NULL, NULL);
if (IS_ERR(hw->clk)) {
ret = PTR_ERR(hw->clk);
goto fail_create_clk; // <- forgot to set hw->clk = NULL
}
The better way to handle errors from loops is to clean up partial
iterations before doing the goto. So add a clk_hw_unregister() if the
dai_clk_lookup = clkdev_hw_create() assignment fails. Then use a
while (--i >= 0) loop in the unwind section:
err_free_all:
i = DA7219_DAI_NUM_CLKS;
err:
while (--i >= 0) {
regards,
dan carpenter
