[PATCH] ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

[PATCH] ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

[Peter Ujfalusi]

When ch_count is smaller than blob->alh_cfg.device_count (e.g. a mono
capture stream, such as a SmartMic, aggregated across multiple SDW
links), step = ch_count / blob->alh_cfg.device_count truncates to 0.
The subsequent GENMASK(step - 1, 0) then underflows step - 1 (u32) to
UINT_MAX, causing GENMASK()'s internal shift to use an out-of-bounds
exponent:

  UBSAN: shift-out-of-bounds in sound/soc/sof/ipc4-topology.c:2363:13
  shift exponent 18446744069414584384 is too large for 64-bit type 'long unsigned int'

Treat ch_count < device_count the same way as the existing "channels
equal to output reference channels" case: apply the same ch_mask to
every aggregated device instead of trying to split channels that
can't be evenly divided.

Fixes: 0390a102cc18 ("ASoC: SOF: ipc4-topology: use different channel mask for each sdw amp feedback")
Cc: stable@vger.kernel.org
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 sound/soc/sof/ipc4-topology.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sound/soc/sof/ipc4-topology.c b/sound/soc/sof/ipc4-topology.c
index f6617dcbf789..c7ff687ecc1d 100644
--- a/sound/soc/sof/ipc4-topology.c
+++ b/sound/soc/sof/ipc4-topology.c
@@ -2473,11 +2473,14 @@ _sof_ipc4_prepare_copier_module(struct snd_sof_widget *swidget,
 				ch_map >>= 4;
 			}
 
-			if (swidget->id == snd_soc_dapm_dai_in && ch_count == out_ref_channels) {
+			if ((swidget->id == snd_soc_dapm_dai_in && ch_count == out_ref_channels) ||
+			    ch_count < blob->alh_cfg.device_count) {
 				/*
 				 * For playback DAI widgets where the channel number is equal to
-				 * the output reference channels, set the step = 0 to ensure all
-				 * the ch_mask is applied to all alh mappings.
+				 * the output reference channels, or when there are fewer
+				 * channels than aggregated devices (e.g. a mono capture
+				 * stream split across multiple links), set step = 0 to
+				 * ensure all the ch_mask is applied to all alh mappings.
 				 */
 				mask = ch_mask;
 				step = 0;
-- 
2.56.0

Re: [PATCH] ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

[Mark Brown]

On Thu, 08 Oct 2026 12:01:30 +0300, Peter Ujfalusi wrote:
> ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-7.3

Thanks!

[1/1] ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture
      https://git.kernel.org/broonie/sound/c/746de48c3a25

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