[PATCH v2] sound: fix uninit-value in sof_ipc4_pcm_dai_link_fixup_rate

[Suraj Sonawane <surajsonawane0215@xxxxxxxxx>]

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'.

This issue occurred because the variable 'be_rate' could remain
uninitialized if num_input_formats is zero. In such cases, the
loop that assigns a value to 'be_rate' would not execute,
potentially leading to undefined behavior when rate->min and
rate->max are set with an uninitialized 'be_rate'.

To resolve this, an additional check for num_input_formats > 0
was added before setting rate->min and rate->max with 'be_rate'.
This ensures that 'be_rate' is assigned only when there are valid
input formats, preventing any use of uninitialized data.

This solution maintains defined behavior for rate->min and rate->max,
ensuring they are only assigned when valid be_rate data is available.

Signed-off-by: Suraj Sonawane <surajsonawane0215@xxxxxxxxx>
---
V1: Initialize 'be_rate' to 0.
V2: Add conditional assignment based on num_input_formats to ensure
be_rate is used only when assigned.

 sound/soc/sof/ipc4-pcm.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sof/ipc4-pcm.c b/sound/soc/sof/ipc4-pcm.c
index 4df2be3d3..d5d7ffc69 100644
--- a/sound/soc/sof/ipc4-pcm.c
+++ b/sound/soc/sof/ipc4-pcm.c
@@ -633,8 +633,11 @@ static int sof_ipc4_pcm_dai_link_fixup_rate(struct snd_sof_dev *sdev,
 			return -EINVAL;
 		}
 
-		rate->min = be_rate;
-		rate->max = rate->min;
+		/* Set rate only if be_rate was assigned */
+		if (num_input_formats > 0) {
+			rate->min = be_rate;
+			rate->max = rate->min;
+		}
 	}
 
 	return 0;
-- 
2.34.1