diff options
authorArjan van de Ven <arjan@infradead.org>2006-07-04 03:07:22 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-04 10:24:57 -0700
commitc6482dde1c2811afba289b2344268f850595f350 (patch)
parent[PATCH] mthca: initialize send and receive queue locks separately (diff)
[PATCH] fix AB-BA deadlock inversion at cs46xx_dsp_remove_scb
There is a code sequence where the locking is substream->self_group.lock -> ins->scbs[index].lock substream->self_group.lock is interrupt safe, and taken from irq context as well (trace is snipped for brevity) so what can happen is cpu 0 cpu 1 user context user context take ins->scbs[index].lock without disabling interrupts get substream->self_group.lock (irqsafe) try to get ins->scbs[index].lock (spins) interrupt happens try to get substream->self_group.lock (spins) which is an obvious AB-BA deadlock fix is to just take the lock with _irqsafe Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Jaroslav Kysela <perex@suse.cz> Acked-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1 files changed, 3 insertions, 2 deletions
diff --git a/sound/pci/cs46xx/dsp_spos_scb_lib.c b/sound/pci/cs46xx/dsp_spos_scb_lib.c
index 3844d18af19c..232b337852ff 100644
--- a/sound/pci/cs46xx/dsp_spos_scb_lib.c
+++ b/sound/pci/cs46xx/dsp_spos_scb_lib.c
@@ -180,6 +180,7 @@ static void _dsp_clear_sample_buffer (struct snd_cs46xx *chip, u32 sample_buffer
void cs46xx_dsp_remove_scb (struct snd_cs46xx *chip, struct dsp_scb_descriptor * scb)
struct dsp_spos_instance * ins = chip->dsp_spos_instance;
+ unsigned long flags;
/* check integrety */
snd_assert ( (scb->index >= 0 &&
@@ -194,9 +195,9 @@ void cs46xx_dsp_remove_scb (struct snd_cs46xx *chip, struct dsp_scb_descriptor *
goto _end);
- spin_lock(&scb->lock);
+ spin_lock_irqsave(&scb->lock, flags);
_dsp_unlink_scb (chip,scb);
- spin_unlock(&scb->lock);
+ spin_unlock_irqrestore(&scb->lock, flags);
snd_assert (scb->scb_symbol != NULL, return );