From: Takashi Iwai Date: Tue, 27 Jan 2015 11:50:44 +0000 (+0100) Subject: ALSA: line6: Fix racy loopback handling X-Git-Tag: firefly_0821_release~176^2~2367^2~35^2~4 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3d3ae4454deb94bbad9ad0b2b559cbf6c0db4ec2;p=firefly-linux-kernel-4.4.55.git ALSA: line6: Fix racy loopback handling The impulse and monitor handling in submit_audio_out_urb() isn't protected thus this can be racy with the capture stream handling. This patch extends the range to protect via each stream's spinlock (now the whole submit_audio_*_urb() are covered), and take the capture stream lock additionally for the impulse and monitor handling part. Tested-by: Chris Rorvick Signed-off-by: Takashi Iwai --- diff --git a/sound/usb/line6/capture.c b/sound/usb/line6/capture.c index 47cfcc2ab387..21342a9dddd7 100644 --- a/sound/usb/line6/capture.c +++ b/sound/usb/line6/capture.c @@ -20,21 +20,19 @@ /* Find a free URB and submit it. + must be called in line6pcm->in.lock context */ static int submit_audio_in_urb(struct snd_line6_pcm *line6pcm) { int index; - unsigned long flags; int i, urb_size; int ret; struct urb *urb_in; - spin_lock_irqsave(&line6pcm->in.lock, flags); index = find_first_zero_bit(&line6pcm->in.active_urbs, LINE6_ISO_BUFFERS); if (index < 0 || index >= LINE6_ISO_BUFFERS) { - spin_unlock_irqrestore(&line6pcm->in.lock, flags); dev_err(line6pcm->line6->ifcdev, "no free URB found\n"); return -EINVAL; } @@ -64,7 +62,6 @@ static int submit_audio_in_urb(struct snd_line6_pcm *line6pcm) dev_err(line6pcm->line6->ifcdev, "URB in #%d submission failed (%d)\n", index, ret); - spin_unlock_irqrestore(&line6pcm->in.lock, flags); return 0; } @@ -73,15 +70,18 @@ static int submit_audio_in_urb(struct snd_line6_pcm *line6pcm) */ int line6_submit_audio_in_all_urbs(struct snd_line6_pcm *line6pcm) { - int ret, i; + unsigned long flags; + int ret = 0, i; + spin_lock_irqsave(&line6pcm->in.lock, flags); for (i = 0; i < LINE6_ISO_BUFFERS; ++i) { ret = submit_audio_in_urb(line6pcm); if (ret < 0) - return ret; + break; } - return 0; + spin_unlock_irqrestore(&line6pcm->in.lock, flags); + return ret; } /* @@ -137,7 +137,9 @@ void line6_capture_check_period(struct snd_line6_pcm *line6pcm, int length) line6pcm->in.bytes += length; if (line6pcm->in.bytes >= line6pcm->in.period) { line6pcm->in.bytes %= line6pcm->in.period; + spin_unlock(&line6pcm->in.lock); snd_pcm_period_elapsed(substream); + spin_lock(&line6pcm->in.lock); } } @@ -196,8 +198,6 @@ static void audio_in_callback(struct urb *urb) if (test_and_clear_bit(index, &line6pcm->in.unlink_urbs)) shutdown = 1; - spin_unlock_irqrestore(&line6pcm->in.lock, flags); - if (!shutdown) { submit_audio_in_urb(line6pcm); @@ -206,6 +206,8 @@ static void audio_in_callback(struct urb *urb) &line6pcm->flags)) line6_capture_check_period(line6pcm, length); } + + spin_unlock_irqrestore(&line6pcm->in.lock, flags); } /* open capture callback */ diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c index 3762a98026aa..b4a26d0c8267 100644 --- a/sound/usb/line6/playback.c +++ b/sound/usb/line6/playback.c @@ -134,11 +134,11 @@ static void add_monitor_signal(struct urb *urb_out, unsigned char *signal, /* Find a free URB, prepare audio data, and submit URB. + must be called in line6pcm->out.lock context */ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) { int index; - unsigned long flags; int i, urb_size, urb_frames; int ret; const int bytes_per_frame = line6pcm->properties->bytes_per_frame; @@ -149,12 +149,10 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) (USB_INTERVALS_PER_SECOND / LINE6_ISO_INTERVAL); struct urb *urb_out; - spin_lock_irqsave(&line6pcm->out.lock, flags); index = find_first_zero_bit(&line6pcm->out.active_urbs, LINE6_ISO_BUFFERS); if (index < 0 || index >= LINE6_ISO_BUFFERS) { - spin_unlock_irqrestore(&line6pcm->out.lock, flags); dev_err(line6pcm->line6->ifcdev, "no free URB found\n"); return -EINVAL; } @@ -187,7 +185,6 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) if (urb_size == 0) { /* can't determine URB size */ - spin_unlock_irqrestore(&line6pcm->out.lock, flags); dev_err(line6pcm->line6->ifcdev, "driver bug: urb_size = 0\n"); return -EINVAL; } @@ -242,7 +239,8 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) urb_out->transfer_buffer_length); } - if (line6pcm->prev_fbuf != NULL) { + spin_lock_nested(&line6pcm->in.lock, SINGLE_DEPTH_NESTING); + if (line6pcm->prev_fbuf) { if (line6pcm->flags & LINE6_BITS_PCM_IMPULSE) { create_impulse_test_signal(line6pcm, urb_out, bytes_per_frame); @@ -266,6 +264,7 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) bytes_per_frame); } } + spin_unlock(&line6pcm->in.lock); ret = usb_submit_urb(urb_out, GFP_ATOMIC); @@ -275,7 +274,6 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) dev_err(line6pcm->line6->ifcdev, "URB out #%d submission failed (%d)\n", index, ret); - spin_unlock_irqrestore(&line6pcm->out.lock, flags); return 0; } @@ -284,15 +282,18 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) */ int line6_submit_audio_out_all_urbs(struct snd_line6_pcm *line6pcm) { - int ret, i; + unsigned long flags; + int ret = 0, i; + spin_lock_irqsave(&line6pcm->out.lock, flags); for (i = 0; i < LINE6_ISO_BUFFERS; ++i) { ret = submit_audio_out_urb(line6pcm); if (ret < 0) - return ret; + break; } - return 0; + spin_unlock_irqrestore(&line6pcm->out.lock, flags); + return ret; } /* @@ -346,8 +347,6 @@ static void audio_out_callback(struct urb *urb) if (test_and_clear_bit(index, &line6pcm->out.unlink_urbs)) shutdown = 1; - spin_unlock_irqrestore(&line6pcm->out.lock, flags); - if (!shutdown) { submit_audio_out_urb(line6pcm); @@ -356,10 +355,13 @@ static void audio_out_callback(struct urb *urb) line6pcm->out.bytes += length; if (line6pcm->out.bytes >= line6pcm->out.period) { line6pcm->out.bytes %= line6pcm->out.period; + spin_unlock(&line6pcm->out.lock); snd_pcm_period_elapsed(substream); + spin_lock(&line6pcm->out.lock); } } } + spin_unlock_irqrestore(&line6pcm->out.lock, flags); } /* open playback callback */