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authorGiuliano Pochini <pochini@shiny.it>2010-02-17 00:57:44 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-02 10:21:26 -0700
commitac633f17d4a5030d5924c1a85bbcde1ad42c3998 (patch)
parentddcd49b943272f275e890e9c1c06cfdbc0a899e3 (diff)
ALSA: Echoaudio, fix Guru Meditation #00000005.48454C50
commit b721e68bdc5b39c51bf6a1469f8d3663fbe03243 upstream. This patch fixes a division by zero error in the irq handler. There is a small window between the hw_params() callback and when runtime->frame_bits is set by ALSA middle layer. When another substream is already running, if an interrupt is delivered during that window the irq handler calls pcm_pointer() which does a division by zero. The patch below makes the irq handler skip substreams that are initialized but not started yet. Cc to Clemens Ladisch because he proposed an alternate fix. For more information, please read the original thread in the linux-kernel mailing list: http://lkml.org/lkml/2010/2/2/187 Signed-off-by: Giuliano Pochini <pochini@shiny.it> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1 files changed, 3 insertions, 1 deletions
diff --git a/sound/pci/echoaudio/echoaudio.c b/sound/pci/echoaudio/echoaudio.c
index 1305f7ca02c3..641d7f07392c 100644
--- a/sound/pci/echoaudio/echoaudio.c
+++ b/sound/pci/echoaudio/echoaudio.c
@@ -1821,7 +1821,9 @@ static irqreturn_t snd_echo_interrupt(int irq, void *dev_id)
/* The hardware doesn't tell us which substream caused the irq,
thus we have to check all running substreams. */
for (ss = 0; ss < DSP_MAXPIPES; ss++) {
- if ((substream = chip->substream[ss])) {
+ substream = chip->substream[ss];
+ if (substream && ((struct audiopipe *)substream->runtime->
+ private_data)->state == PIPE_STATE_STARTED) {
period = pcm_pointer(substream) /
if (period != chip->last_period[ss]) {