Fix an issue detected by the Smatch tool:

sound/soc/sof/ipc4-pcm.c: sof_ipc4_pcm_dai_link_fixup_rate()
error: uninitialized symbol 'be_rate'.

The warning highlights a case where `be_rate` could remain uninitialized
if `num_input_formats` is zero, which would cause undefined behavior
when setting `rate->min` and `rate->max` based on `be_rate`.

To address this issue, a `WARN_ON_ONCE(!num_input_formats)` check was
added to ensure `num_input_formats` is greater than zero. If this
condition fails, the function returns `-EINVAL`, preventing the use of
an uninitialized `be_rate`.

This change improves the robustness of the function by catching an
invalid state early and providing better feedback during development.

Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>
---
V1: Initialize 'be_rate' to 0.
V2: Add conditional assignment based on num_input_formats to ensure
be_rate is used only when assigned.
V3: Add WARN_ON_ONCE check to handle the case where num_input_formats
is zero, ensuring proper error handling for uninitialized be_rate.

 sound/soc/sof/ipc4-pcm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/soc/sof/ipc4-pcm.c b/sound/soc/sof/ipc4-pcm.c
index 4df2be3d3..18fff2df7 100644
--- a/sound/soc/sof/ipc4-pcm.c
+++ b/sound/soc/sof/ipc4-pcm.c
@@ -603,6 +603,9 @@ static int sof_ipc4_pcm_dai_link_fixup_rate(struct snd_sof_dev *sdev,
 	unsigned int be_rate;
 	int i;
 
+	if (WARN_ON_ONCE(!num_input_formats))
+		return -EINVAL;
+
 	/*
 	 * Copier does not change sampling rate, so we
 	 * need to only consider the input pin information.
-- 
2.34.1

On Thu, 07 Nov 2024 12:06:09 +0530, Suraj Sonawane wrote:
> Fix an issue detected by the Smatch tool:
> 
> sound/soc/sof/ipc4-pcm.c: sof_ipc4_pcm_dai_link_fixup_rate()
> error: uninitialized symbol 'be_rate'.
> 
> The warning highlights a case where `be_rate` could remain uninitialized
> if `num_input_formats` is zero, which would cause undefined behavior
> when setting `rate->min` and `rate->max` based on `be_rate`.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoc: SOF: ipc4-pcm: fix uninit-value in sof_ipc4_pcm_dai_link_fixup_rate
      commit: 9a59718a5340aa0240a442115eb499de2ed18ee4

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark