Re: [PATCH 2/3] ASoC: codecs: wcd9335: Remove potential undefined behavior in wcd9335_slimbus_irq()

[Srinivas Kandagatla <srini@kernel.org>]

On 3/9/26 4:03 PM, Josh Poimboeuf wrote:
> If 'port_id' is negative, the shift counts in wcd9335_slimbus_irq() also
> become negative, resulting in undefined behavior due to shift out of
> bounds.
> 
> That appears to be not possible, but with UBSAN enabled, Clang's range
> analysis isn't always able to determine that and generates undefined
> behavior.
> 
> As a result the code generation isn't optimal, and undefined behavior
> should be avoided regardless.  Improve code generation and remove the
> undefined behavior by converting the signed variables to unsigned.
> 
> Fixes the following warning:
> 
>   sound/soc/codecs/wcd9335.o: warning: objtool: wcd9335_slimbus_irq() falls through to next function __cfi_wcd9335_set_channel_map()
> 
> This is very similar to a previous fix to wcd934x with commit
> 060aed9c0093 ("objtool, ASoC: codecs: wcd934x: Remove potential
> undefined behavior in wcd934x_slim_irq_handler()").
> 
> Cc: Srinivas Kandagatla <srini@kernel.org>
> Cc: Liam Girdwood <lgirdwood@gmail.com>
> Cc: Mark Brown <broonie@kernel.org>
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
> ---

Am not sure if port_id will be ever negative. but the change itself
looks harmless,

Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>

--srini

>  sound/soc/codecs/wcd9335.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/wcd9335.c b/sound/soc/codecs/wcd9335.c
> index 640e43ee1975..e3ca5ca6de3d 100644
> --- a/sound/soc/codecs/wcd9335.c
> +++ b/sound/soc/codecs/wcd9335.c
> @@ -3907,7 +3907,7 @@ static irqreturn_t wcd9335_slimbus_irq(int irq, void *data)
>  {
>  	struct wcd9335_codec *wcd = data;
>  	unsigned long status = 0;
> -	int i, j, port_id;
> +	unsigned int i, j, port_id;
>  	unsigned int val, int_val = 0;
>  	irqreturn_t ret = IRQ_NONE;
>  	bool tx;