Re: [PATCH v7 3/5] misc: fastrpc: Fail Audio PD init when reserved memory is missing

[Jianping Li <jianping.li@oss.qualcomm.com>]

On 6/8/2026 2:11 PM, Dmitry Baryshkov wrote:
> On Tue, Jun 02, 2026 at 03:17:48PM +0800, Jianping Li wrote:
>> Audio PD static process creation assumes that a reserved-memory
>> region is defined in DT and exposed via cctx->remote_heap.
>>
>> If reserved-memory is missing or incomplete, the driver may pass
>> invalid address/size information to the DSP, leading to undefined
>> behavior or crashes.
>>
>> Add explicit validation for remote_heap presence and size before
>> sending the memory to DSP, and fail early if the configuration is
>> invalid.
>>
>> Fixes: 0871561055e66 ("misc: fastrpc: Add support for audiopd")
>> Cc: stable@kernel.org
>> Signed-off-by: Jianping Li <jianping.li@oss.qualcomm.com>
>> ---
>>   drivers/misc/fastrpc.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
>> index a8a58f889d07..f46a8f53970d 100644
>> --- a/drivers/misc/fastrpc.c
>> +++ b/drivers/misc/fastrpc.c
>> @@ -1354,6 +1354,13 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
>>   	} inbuf;
>>   	u32 sc;
>>   
>> +	if (!fl->cctx->remote_heap ||
>> +	    !fl->cctx->remote_heap->dma_addr ||
>> +	    !fl->cctx->remote_heap->size) {
>> +		err = -ENOMEM;
>> +		dev_dbg(fl->sctx->dev, "remote heap memory region is not added\n");
>> +		return err;
>> +	}
> Won't this check without the next commit break the kernel? I don't see
> where else the remote heap is being allocated.

Yes, this check depends on remote_heap being populated during rpmsg
probe from the reserved-memory region, introduced in a subsequent
patch in this series.

If there is no dependency on the next series, the remote_heap allocation here after the if check.
The logic will be wrong.

>
>>   	args = kzalloc_objs(*args, FASTRPC_CREATE_STATIC_PROCESS_NARGS);
>>   	if (!args)
>>   		return -ENOMEM;
>> -- 
>> 2.43.0
>>