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dax: fix race condition on the tuning buffer #11056

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9fd06e9
dax: update p_dax pointer state on mock version
checkupup Jun 4, 2026
ab9a656
dax: fix race condition on the tuning buffer
checkupup Jun 4, 2026
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58 changes: 46 additions & 12 deletions src/audio/module_adapter/module/dolby/dax.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ SOF_DEFINE_REG_UUID(dolby_dax_audio_processing);
#define DAX_CP_MASK 0x8
#define DAX_VOLUME_MASK 0x10
#define DAX_CTC_MASK 0x20
#define DAX_TUNING_FILE_MASK 0x40
#define DAX_PROCESSING_MASK 0x10000
#define DAX_RESET_MASK 0x20000
#define DAX_FREE_MASK 0x40000
Expand Down Expand Up @@ -241,24 +242,27 @@ static bool is_enabled(struct processing_module *mod)
return dax_ctx->enable && dax_ctx->p_dax;
}

static int set_tuning_file(struct processing_module *mod, void *value, uint32_t size)
static int set_tuning_file(struct processing_module *mod)
{
int ret = 0;
int ret = -EINVAL;
struct comp_dev *dev = mod->dev;
struct dax_adapter_data *adapter_data = module_get_private_data(mod);
struct sof_dax *dax_ctx = &adapter_data->dax_ctx;
struct dax_buffer old_tuning_buf = {0};
k_spinlock_key_t key;

if (dax_buffer_alloc(mod, &dax_ctx->tuning_file_buffer, size) != 0) {
comp_err(dev, "allocate %u bytes failed for tuning file", size);
ret = -ENOMEM;
} else {
memcpy_s(dax_ctx->tuning_file_buffer.addr,
dax_ctx->tuning_file_buffer.free,
value,
size);
key = k_spin_lock(&adapter_data->lock);

@lyakh lyakh Aug 6, 2026

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I suppose you're implicitly using the fact, that this function only runs in IPC context, when its priority is lower than the processing function? Although IIRC you also support running in DP mode, not sure this priority promise will also always hold for that case. So I suppose you'd need to take the lock in the critical part of the processing function too - where this tuning buffer is used there.

@checkupup checkupup Aug 6, 2026

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Good point, and I agree we should not rely on an IPC-priority assumption, especially with DP mode in mind.

Also, the active buffer (dax_ctx->tuning_file_buffer) is only switched from the processing path (check_and_update_settings() -> set_tuning_file()), so we do not need to lock the other parts of the processing function.

I think I should add a lock in dax_set_param_wrapper as well to prevent access to same tuning buffer object.

if (adapter_data->cache_tuning_buf.addr && adapter_data->cache_tuning_buf.size > 0) {
old_tuning_buf = dax_ctx->tuning_file_buffer;
dax_ctx->tuning_file_buffer = adapter_data->cache_tuning_buf;
adapter_data->cache_tuning_buf = (struct dax_buffer){0};
ret = 0;
}
k_spin_unlock(&adapter_data->lock, key);

dax_buffer_release(mod, &old_tuning_buf);

comp_info(dev, "allocated: tuning %u, ret %d", dax_ctx->tuning_file_buffer.size, ret);
comp_info(dev, "apply tuning %p, ret %d", dax_ctx->tuning_file_buffer.addr, ret);
return ret;
}

Expand Down Expand Up @@ -363,11 +367,33 @@ static int dax_set_param_wrapper(struct processing_module *mod,
struct comp_dev *dev = mod->dev;
struct dax_adapter_data *adapter_data = module_get_private_data(mod);
struct sof_dax *dax_ctx = &adapter_data->dax_ctx;
struct dax_buffer new_tuning_buf = { 0 };
struct dax_buffer old_tuning_buf = { 0 };
k_spinlock_key_t key;
int32_t tmp_val;

switch (id) {
case DAX_PARAM_ID_TUNING_FILE:
set_tuning_file(mod, value, size);
ret = dax_buffer_alloc(mod, &new_tuning_buf, size);
if (ret != 0) {
comp_err(dev, "allocate %u bytes failed for tuning file, ret %d", size,
ret);
break;
}
ret = memcpy_s(new_tuning_buf.addr, new_tuning_buf.free, value, size);
if (ret != 0) {
comp_err(dev, "copy tuning file failed, ret %d", ret);
dax_buffer_release(mod, &new_tuning_buf);
break;
}
key = k_spin_lock(&adapter_data->lock);
old_tuning_buf = adapter_data->cache_tuning_buf;
adapter_data->cache_tuning_buf = new_tuning_buf;
k_spin_unlock(&adapter_data->lock, key);
dax_buffer_release(mod, &old_tuning_buf);
flag_process(adapter_data, DAX_TUNING_FILE_MASK, DAX_FLAG_SET);
comp_info(dev, "allocated: tuning %p, size %u", new_tuning_buf.addr,
new_tuning_buf.size);
break;
case DAX_PARAM_ID_ENABLE:
tmp_val = *((int32_t *)value);
Expand Down Expand Up @@ -488,6 +514,12 @@ static void check_and_update_settings(struct processing_module *mod)
if (!is_enabled(mod))
return;

if (flag_process(adapter_data, DAX_TUNING_FILE_MASK, DAX_FLAG_READ_AND_CLEAR)) {
set_tuning_file(mod);
flag_process(adapter_data, DAX_DEVICE_MASK, DAX_FLAG_SET);
flag_process(adapter_data, DAX_VOLUME_MASK, DAX_FLAG_SET);
}

if (flag_process(adapter_data, DAX_DEVICE_MASK, DAX_FLAG_READ_AND_CLEAR)) {
set_device(mod, dax_ctx->out_device);
set_tuning_device(mod, dax_ctx->tuning_device);
Expand Down Expand Up @@ -547,6 +579,7 @@ static int sof_dax_free(struct processing_module *mod)
dax_buffer_release(mod, &dax_ctx->tuning_file_buffer);
mod_data_blob_handler_free(mod, dax_ctx->blob_handler);
dax_ctx->blob_handler = NULL;
dax_buffer_release(mod, &adapter_data->cache_tuning_buf);
mod_free(mod, adapter_data);
module_set_private_data(mod, NULL);
}
Expand Down Expand Up @@ -584,6 +617,7 @@ static int sof_dax_init(struct processing_module *mod)
adapter_data = module_get_private_data(mod);
adapter_data->comp_id = dev->ipc_config.id;
adapter_data->priority = DAX_USER_PRIORITY_DEFAULT;
k_spinlock_init(&adapter_data->lock);
dax_ctx = &adapter_data->dax_ctx;
dax_ctx->enable = 0;
dax_ctx->profile = 0;
Expand Down
3 changes: 3 additions & 0 deletions src/audio/module_adapter/module/dolby/dax.h
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Expand Up @@ -7,6 +7,7 @@
* Author: Jun Lai <jun.lai@dolby.com>
*/

#include <rtos/spinlock.h>
#include <sof/audio/module_adapter/module/generic.h>
#include <dax_inf.h>

Expand All @@ -24,6 +25,8 @@ struct dax_adapter_data {
atomic_t proc_flags;
uint32_t comp_id;
int32_t priority;
struct dax_buffer cache_tuning_buf;
struct k_spinlock lock;
};

/**
Expand Down
4 changes: 3 additions & 1 deletion src/audio/module_adapter/module/dolby/dax_mock.c
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Expand Up @@ -29,11 +29,13 @@ uint32_t dax_query_period_frames(struct sof_dax *dax_ctx)

int dax_free(struct sof_dax *dax_ctx)
{
dax_ctx->p_dax = NULL;
return 0;
}

int dax_init(struct sof_dax *dax_ctx)
{
dax_ctx->p_dax = dax_ctx->persist_buffer.addr;
return 0;
}

Expand Down Expand Up @@ -81,7 +83,7 @@ int dax_set_ctc_enable(int32_t enable, struct sof_dax *dax_ctx)

const char *dax_get_version(void)
{
return "";
return "mock_version";

@lyakh lyakh Aug 6, 2026

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does C guarantee that this string is allocated in some permanent section and not on stack?

@checkupup checkupup Aug 6, 2026

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Yes, string literals are guaranteed to have static storage duration in C.

}

void *dax_find_params(uint32_t query_id,
Expand Down
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