Return-Path: MIME-Version: 1.0 In-Reply-To: <1400764022-26666-1-git-send-email-Andrei.Emeltchenko.news@gmail.com> References: <1400764022-26666-1-git-send-email-Andrei.Emeltchenko.news@gmail.com> From: Andrzej Kaczmarek Date: Thu, 22 May 2014 15:54:34 +0200 Message-ID: Subject: Re: [RFC] android/hal-audio: Fix wrong memory access To: Andrei Emeltchenko Cc: linux-bluetooth Content-Type: text/plain; charset=UTF-8 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Andrei, On 22 May 2014 15:07, Andrei Emeltchenko wrote: > From: Andrei Emeltchenko > > downmix_buf is allocated to have buffer size FIXED_BUFFER_SIZE / 2, when > we access it as (int16_t *) we shall device index by 2. > --- > android/hal-audio.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/android/hal-audio.c b/android/hal-audio.c > index 7305bb6..96fa5c3 100644 > --- a/android/hal-audio.c > +++ b/android/hal-audio.c > @@ -984,7 +984,7 @@ static void downmix_to_mono(struct a2dp_stream_out *out, const uint8_t *buffer, > int16_t *output = (void *) out->downmix_buf; > size_t i; > > - for (i = 0; i < bytes / 2; i++) { > + for (i = 0; i < bytes / (2 * sizeof(int16_t)); i++) { > int16_t l = le16_to_cpu(get_unaligned(&input[i * 2])); > int16_t r = le16_to_cpu(get_unaligned(&input[i * 2 + 1])); Fix is correct, but commit message does not explain properly why this is required. Basically we need to downmix X frames from input buffer and this number is "bytes / (number_of_channels * sample_size)" - so we were missing "sample_size" here. I think adding inline comment to explain this would be also good. BR, Andrzej