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authorKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>2023-11-24 19:01:36 +0100
committerVinod Koul <vkoul@kernel.org>2023-11-28 12:28:16 +0530
commite199bf52ffda8f98f129728d57244a9cd9ad5623 (patch)
treef4e2f89f649ba748d7f611642499962628f36b00
parentb85ea95d086471afb4ad062012a4d73cd328fa86 (diff)
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soundwire: stream: fix NULL pointer dereference for multi_link
If bus is marked as multi_link, but number of masters in the stream is not higher than bus->hw_sync_min_links (bus->multi_link && m_rt_count >= bus->hw_sync_min_links), bank switching should not happen. The first part of do_bank_switch() code properly takes these conditions into account, but second part (sdw_ml_sync_bank_switch()) relies purely on bus->multi_link property. This is not balanced and leads to NULL pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 ... Call trace: wait_for_completion_timeout+0x124/0x1f0 do_bank_switch+0x370/0x6f8 sdw_prepare_stream+0x2d0/0x438 qcom_snd_sdw_prepare+0xa0/0x118 sm8450_snd_prepare+0x128/0x148 snd_soc_link_prepare+0x5c/0xe8 __soc_pcm_prepare+0x28/0x1ec dpcm_be_dai_prepare+0x1e0/0x2c0 dpcm_fe_dai_prepare+0x108/0x28c snd_pcm_do_prepare+0x44/0x68 snd_pcm_action_single+0x54/0xc0 snd_pcm_action_nonatomic+0xe4/0xec snd_pcm_prepare+0xc4/0x114 snd_pcm_common_ioctl+0x1154/0x1cc0 snd_pcm_ioctl+0x54/0x74 Fixes: ce6e74d008ff ("soundwire: Add support for multi link bank switch") Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Link: https://lore.kernel.org/r/20231124180136.390621-1-krzysztof.kozlowski@linaro.org Signed-off-by: Vinod Koul <vkoul@kernel.org>
-rw-r--r--drivers/soundwire/stream.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 69719b335bcb..f048b3d55b2e 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -742,14 +742,15 @@ error_1:
* sdw_ml_sync_bank_switch: Multilink register bank switch
*
* @bus: SDW bus instance
+ * @multi_link: whether this is a multi-link stream with hardware-based sync
*
* Caller function should free the buffers on error
*/
-static int sdw_ml_sync_bank_switch(struct sdw_bus *bus)
+static int sdw_ml_sync_bank_switch(struct sdw_bus *bus, bool multi_link)
{
unsigned long time_left;
- if (!bus->multi_link)
+ if (!multi_link)
return 0;
/* Wait for completion of transfer */
@@ -847,7 +848,7 @@ static int do_bank_switch(struct sdw_stream_runtime *stream)
bus->bank_switch_timeout = DEFAULT_BANK_SWITCH_TIMEOUT;
/* Check if bank switch was successful */
- ret = sdw_ml_sync_bank_switch(bus);
+ ret = sdw_ml_sync_bank_switch(bus, multi_link);
if (ret < 0) {
dev_err(bus->dev,
"multi link bank switch failed: %d\n", ret);