Fix an issue detected by the Smatch tool:

sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
error: uninitialized symbol 'val_1'.
sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
error: uninitialized symbol 'val_2'.

These errors were triggered because the variables 'val_1' and 'val_2'
could remain uninitialized if 'offlevel' is zero, meaning the loop
that assigns values to them does not execute. In this case,
'dma_addr_next' would use uninitialized data, potentially leading
to undefined behavior.

To resolve this, a conditional update for 'dma_addr_next' is added,
ensuring it is assigned only when 'val_1' and 'val_2' are read.
A new boolean variable 'val_read' flags when the values have been
retrieved, setting 'dma_addr_next' only if valid data is available.

This solution prevents the use of uninitialized data, maintaining
defined behavior for 'dma_addr_next' in all cases, and aligns with
expected usage of I2S RX descriptor data.

Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>
---
V1: Initialize 'val_1' and 'val_2' to 0.
V2: Add conditional update for 'dma_addr_next' based on read status to
skip the update when values haven’t been read.

 sound/soc/bcm/bcm63xx-pcm-whistler.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sound/soc/bcm/bcm63xx-pcm-whistler.c b/sound/soc/bcm/bcm63xx-pcm-whistler.c
index 018f2372e..e3a4fcc63 100644
--- a/sound/soc/bcm/bcm63xx-pcm-whistler.c
+++ b/sound/soc/bcm/bcm63xx-pcm-whistler.c
@@ -256,12 +256,16 @@ static irqreturn_t i2s_dma_isr(int irq, void *bcm_i2s_priv)
 
 		offlevel = (int_status & I2S_RX_DESC_OFF_LEVEL_MASK) >>
 			   I2S_RX_DESC_OFF_LEVEL_SHIFT;
+		bool val_read = false;
 		while (offlevel) {
 			regmap_read(regmap_i2s, I2S_RX_DESC_OFF_ADDR, &val_1);
 			regmap_read(regmap_i2s, I2S_RX_DESC_OFF_LEN, &val_2);
+			val_read = true;
 			offlevel--;
 		}
-		prtd->dma_addr_next = val_1 + val_2;
+		if (val_read)
+			prtd->dma_addr_next = val_1 + val_2;
+
 		ifflevel = (int_status & I2S_RX_DESC_IFF_LEVEL_MASK) >>
 			   I2S_RX_DESC_IFF_LEVEL_SHIFT;
 
-- 
2.34.1

On Sat, 02 Nov 2024 18:06:30 +0530, Suraj Sonawane wrote:
> Fix an issue detected by the Smatch tool:
> 
> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
> error: uninitialized symbol 'val_1'.
> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
> error: uninitialized symbol 'val_2'.
> 
> [...]

Applied to

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

Thanks!

[1/1] sound: fix uninit-value in i2s_dma_isr
      commit: 28f7aa0c015036db260adbec37891984a31ed4c2

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

On 05/11/24 22:08, Mark Brown wrote:
> On Sat, 02 Nov 2024 18:06:30 +0530, Suraj Sonawane wrote:
>> Fix an issue detected by the Smatch tool:
>>
>> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
>> error: uninitialized symbol 'val_1'.
>> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
>> error: uninitialized symbol 'val_2'.
>>
>> [...]
> 
> Applied to
> 
>     https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next
> 
> Thanks!
> 
> [1/1] sound: fix uninit-value in i2s_dma_isr
>        commit: 28f7aa0c015036db260adbec37891984a31ed4c2
> 
> 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
> 
Thank you so much!
I appreciate the update.
I’ll monitor for any follow-up feedback.

Best regards,
Suraj Sonawane

On Sat, Nov 02, 2024 at 06:06:30PM +0530, Suraj Sonawane wrote:
> Fix an issue detected by the Smatch tool:
> 
> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
> error: uninitialized symbol 'val_1'.
> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
> error: uninitialized symbol 'val_2'.

Please submit patches using subject lines reflecting the style for the
subsystem, this makes it easier for people to identify relevant patches.
Look at what existing commits in the area you're changing are doing and
make sure your subject lines visually resemble what they're doing.
There's no need to resubmit to fix this alone.

Please don't send new patches in reply to old patches or serieses, this
makes it harder for both people and tools to understand what is going
on - it can bury things in mailboxes and make it difficult to keep track
of what current patches are, both for the new patches and the old ones.

On 04/11/24 18:11, Mark Brown wrote:
> On Sat, Nov 02, 2024 at 06:06:30PM +0530, Suraj Sonawane wrote:
>> Fix an issue detected by the Smatch tool:
>>
>> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
>> error: uninitialized symbol 'val_1'.
>> sound/soc/bcm/bcm63xx-pcm-whistler.c:264 i2s_dma_isr()
>> error: uninitialized symbol 'val_2'.
> 
> Please submit patches using subject lines reflecting the style for the
> subsystem, this makes it easier for people to identify relevant patches.
> Look at what existing commits in the area you're changing are doing and
> make sure your subject lines visually resemble what they're doing.
> There's no need to resubmit to fix this alone.
> 
> Please don't send new patches in reply to old patches or serieses, this
> makes it harder for both people and tools to understand what is going
> on - it can bury things in mailboxes and make it difficult to keep track
> of what current patches are, both for the new patches and the old ones.

Thank you for the guidance. I understand the importance of following the 
existing format for subject lines to maintain consistency within the 
subsystem. When I submitted the v2 patch earlier, I had been considering 
this, but I mistakenly thought that switching subject lines between v1 
and v2 wasn’t necessary. Moving forward, I'll make sure my patches align 
with the the style for the subsystem and will submit them as new threads 
to avoid confusion.

Thank you again for your feedback.