| Message ID | 20241106014654.206860-1-luoyifan@cmss.chinamobile.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ASoC: stm: Prevent potential division by zero in stm32_sai_mclk_round_rate() | expand |
Hi Luo, On 11/6/24 02:46, Luo Yifan wrote: > This patch checks if div is less than or equal to zero (div <= 0). If > div is zero or negative, the function returns -EINVAL, ensuring the > division operation (*prate / div) is safe to perform. > > Signed-off-by: Luo Yifan <luoyifan@cmss.chinamobile.com> > --- > sound/soc/stm/stm32_sai_sub.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c > index 7bc4a96b7..2570daa3e 100644 > --- a/sound/soc/stm/stm32_sai_sub.c > +++ b/sound/soc/stm/stm32_sai_sub.c > @@ -378,8 +378,8 @@ static long stm32_sai_mclk_round_rate(struct clk_hw *hw, unsigned long rate, > int div; > > div = stm32_sai_get_clk_div(sai, *prate, rate); > - if (div < 0) > - return div; > + if (div <= 0) > + return -EINVAL; > > mclk->freq = *prate / div; > Thanks for your patch. It looks fine, but I think that it has to be extended. In CR1 register, MCKDIV = 0 gives the same result as MCKDIV = 1. But while MCKDIV = 0 is valid, for sure div = 0 is not valid. I agree that that div = 0 has to be managed as an error This could be rather handled in stm32_sai_get_clk_div() function itself, by returning an error, if div is null. This is relevant as we may also get an error on test "if (input_rate % div)". I suggest to add a specific test and error message to handle this case in stm32_sai_get_clk_div(). Something like: if (!div)) { dev_err(&sai->pdev->dev, "Invalid null divider\n"); return -EINVAL; } BRs Olivier
Sure, I can submit a new patch with specific tests and error messages added to stm32_sai_get_clk_div().
diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c index 7bc4a96b7..2570daa3e 100644 --- a/sound/soc/stm/stm32_sai_sub.c +++ b/sound/soc/stm/stm32_sai_sub.c @@ -378,8 +378,8 @@ static long stm32_sai_mclk_round_rate(struct clk_hw *hw, unsigned long rate, int div; div = stm32_sai_get_clk_div(sai, *prate, rate); - if (div < 0) - return div; + if (div <= 0) + return -EINVAL; mclk->freq = *prate / div;
This patch checks if div is less than or equal to zero (div <= 0). If div is zero or negative, the function returns -EINVAL, ensuring the division operation (*prate / div) is safe to perform. Signed-off-by: Luo Yifan <luoyifan@cmss.chinamobile.com> --- sound/soc/stm/stm32_sai_sub.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)