From 670777a91580ec7e34d879c3973927f748be6f47 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?K=C5=91v=C3=A1g=C3=B3=2C=20Zolt=C3=A1n?= Date: Sun, 13 Oct 2019 21:58:06 +0200 Subject: [PATCH] usbaudio: change playback counters to 64 bit MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With stereo playback, they need about 375 minutes of continuous audio playback to overflow, which is usually not a problem (as stopping and later resuming playback resets the counters). But with 7.1 audio, they only need about 95 minutes to overflow. After the overflow, the buf->prod % USBAUDIO_PACKET_SIZE(channels) assertion no longer holds true, which will result in overflowing the buffer. With 64 bit variables, it would take about 762000 years to overflow. Signed-off-by: Kővágó, Zoltán Message-id: ff866985ed369f1e18ea7c70da6a7fce8e241deb.1570996490.git.DirtY.iCE.hu@gmail.com Signed-off-by: Gerd Hoffmann --- hw/usb/dev-audio.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/hw/usb/dev-audio.c b/hw/usb/dev-audio.c index e42bdfbdc1..ea604bbb8e 100644 --- a/hw/usb/dev-audio.c +++ b/hw/usb/dev-audio.c @@ -578,9 +578,9 @@ static const USBDesc desc_audio_multi = { struct streambuf { uint8_t *data; - uint32_t size; - uint32_t prod; - uint32_t cons; + size_t size; + uint64_t prod; + uint64_t cons; }; static void streambuf_init(struct streambuf *buf, uint32_t size, @@ -601,7 +601,7 @@ static void streambuf_fini(struct streambuf *buf) static int streambuf_put(struct streambuf *buf, USBPacket *p, uint32_t channels) { - uint32_t free = buf->size - (buf->prod - buf->cons); + int64_t free = buf->size - (buf->prod - buf->cons); if (free < USBAUDIO_PACKET_SIZE(channels)) { return 0; @@ -610,6 +610,8 @@ static int streambuf_put(struct streambuf *buf, USBPacket *p, uint32_t channels) return 0; } + /* can happen if prod overflows */ + assert(buf->prod % USBAUDIO_PACKET_SIZE(channels) == 0); usb_packet_copy(p, buf->data + (buf->prod % buf->size), USBAUDIO_PACKET_SIZE(channels)); buf->prod += USBAUDIO_PACKET_SIZE(channels); @@ -618,10 +620,10 @@ static int streambuf_put(struct streambuf *buf, USBPacket *p, uint32_t channels) static uint8_t *streambuf_get(struct streambuf *buf, size_t *len) { - uint32_t used = buf->prod - buf->cons; + int64_t used = buf->prod - buf->cons; uint8_t *data; - if (!used) { + if (used <= 0) { *len = 0; return NULL; }