[ALSA] Fix potential NULL pointer dereference in echoaudio midi

Fix races between the timer handler and the close function.

Signed-off-by: Giuliano Pochini <pochini@shiny.it>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
This commit is contained in:
Giuliano Pochini 2006-11-06 11:42:00 +01:00 committed by Jaroslav Kysela
parent 5b005a0126
commit 5929546a96

View File

@ -213,7 +213,7 @@ static void snd_echo_midi_output_write(unsigned long data)
sent = bytes = 0;
spin_lock_irqsave(&chip->lock, flags);
chip->midi_full = 0;
if (chip->midi_out && !snd_rawmidi_transmit_empty(chip->midi_out)) {
if (!snd_rawmidi_transmit_empty(chip->midi_out)) {
bytes = snd_rawmidi_transmit_peek(chip->midi_out, buf,
MIDI_OUT_BUFFER_SIZE - 1);
DE_MID(("Try to send %d bytes...\n", bytes));
@ -264,9 +264,11 @@ static void snd_echo_midi_output_trigger(struct snd_rawmidi_substream *substream
}
} else {
if (chip->tinuse) {
del_timer(&chip->timer);
chip->tinuse = 0;
spin_unlock_irq(&chip->lock);
del_timer_sync(&chip->timer);
DE_MID(("Timer removed\n"));
return;
}
}
spin_unlock_irq(&chip->lock);