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authorLinus Torvalds <torvalds@linux-foundation.org>2016-02-19 08:01:41 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-02-19 08:01:41 -0800
commit9001b8e4f08dd7ae8429214979bd7783160932c5 (patch)
tree38a3babfeb313d2572f45ff4c4607dc7d5dccd80
parent705d43dbe10d6e213a75187ac92b61f9bd00af0b (diff)
parent67ec1072b053c15564e6090ab30127895dc77a89 (diff)
Merge tag 'sound-4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai: "This update contains again a few more fixes for ALSA core stuff although it's no longer high flux: two race fixes in sequencer and one PCM race fix for non-atomic PCM ops. In addition, HD-audio gained a similar fix for race at reloading the driver" * tag 'sound-4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: ALSA: pcm: Fix rwsem deadlock for non-atomic PCM stream ALSA: seq: Fix double port list deletion ALSA: hda - Cancel probe work instead of flush at remove ALSA: seq: Fix leak of pool buffer at concurrent writes
-rw-r--r--sound/core/pcm_native.c16
-rw-r--r--sound/core/seq/seq_memory.c13
-rw-r--r--sound/core/seq/seq_ports.c13
-rw-r--r--sound/pci/hda/hda_intel.c4
4 files changed, 33 insertions, 13 deletions
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index fadd3eb8e8bb..9106d8e2300e 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -74,6 +74,18 @@ static int snd_pcm_open(struct file *file, struct snd_pcm *pcm, int stream);
static DEFINE_RWLOCK(snd_pcm_link_rwlock);
static DECLARE_RWSEM(snd_pcm_link_rwsem);
+/* Writer in rwsem may block readers even during its waiting in queue,
+ * and this may lead to a deadlock when the code path takes read sem
+ * twice (e.g. one in snd_pcm_action_nonatomic() and another in
+ * snd_pcm_stream_lock()). As a (suboptimal) workaround, let writer to
+ * spin until it gets the lock.
+ */
+static inline void down_write_nonblock(struct rw_semaphore *lock)
+{
+ while (!down_write_trylock(lock))
+ cond_resched();
+}
+
/**
* snd_pcm_stream_lock - Lock the PCM stream
* @substream: PCM substream
@@ -1813,7 +1825,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd)
res = -ENOMEM;
goto _nolock;
}
- down_write(&snd_pcm_link_rwsem);
+ down_write_nonblock(&snd_pcm_link_rwsem);
write_lock_irq(&snd_pcm_link_rwlock);
if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN ||
substream->runtime->status->state != substream1->runtime->status->state ||
@@ -1860,7 +1872,7 @@ static int snd_pcm_unlink(struct snd_pcm_substream *substream)
struct snd_pcm_substream *s;
int res = 0;
- down_write(&snd_pcm_link_rwsem);
+ down_write_nonblock(&snd_pcm_link_rwsem);
write_lock_irq(&snd_pcm_link_rwlock);
if (!snd_pcm_stream_linked(substream)) {
res = -EALREADY;
diff --git a/sound/core/seq/seq_memory.c b/sound/core/seq/seq_memory.c
index 801076687bb1..c850345c43b5 100644
--- a/sound/core/seq/seq_memory.c
+++ b/sound/core/seq/seq_memory.c
@@ -383,15 +383,20 @@ int snd_seq_pool_init(struct snd_seq_pool *pool)
if (snd_BUG_ON(!pool))
return -EINVAL;
- if (pool->ptr) /* should be atomic? */
- return 0;
- pool->ptr = vmalloc(sizeof(struct snd_seq_event_cell) * pool->size);
- if (!pool->ptr)
+ cellptr = vmalloc(sizeof(struct snd_seq_event_cell) * pool->size);
+ if (!cellptr)
return -ENOMEM;
/* add new cells to the free cell list */
spin_lock_irqsave(&pool->lock, flags);
+ if (pool->ptr) {
+ spin_unlock_irqrestore(&pool->lock, flags);
+ vfree(cellptr);
+ return 0;
+ }
+
+ pool->ptr = cellptr;
pool->free = NULL;
for (cell = 0; cell < pool->size; cell++) {
diff --git a/sound/core/seq/seq_ports.c b/sound/core/seq/seq_ports.c
index 921fb2bd8fad..fe686ee41c6d 100644
--- a/sound/core/seq/seq_ports.c
+++ b/sound/core/seq/seq_ports.c
@@ -535,19 +535,22 @@ static void delete_and_unsubscribe_port(struct snd_seq_client *client,
bool is_src, bool ack)
{
struct snd_seq_port_subs_info *grp;
+ struct list_head *list;
+ bool empty;
grp = is_src ? &port->c_src : &port->c_dest;
+ list = is_src ? &subs->src_list : &subs->dest_list;
down_write(&grp->list_mutex);
write_lock_irq(&grp->list_lock);
- if (is_src)
- list_del(&subs->src_list);
- else
- list_del(&subs->dest_list);
+ empty = list_empty(list);
+ if (!empty)
+ list_del_init(list);
grp->exclusive = 0;
write_unlock_irq(&grp->list_lock);
up_write(&grp->list_mutex);
- unsubscribe_port(client, port, grp, &subs->info, ack);
+ if (!empty)
+ unsubscribe_port(client, port, grp, &subs->info, ack);
}
/* connect two ports */
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 4045dca3d699..ce6b97f31390 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -2168,10 +2168,10 @@ static void azx_remove(struct pci_dev *pci)
struct hda_intel *hda;
if (card) {
- /* flush the pending probing work */
+ /* cancel the pending probing work */
chip = card->private_data;
hda = container_of(chip, struct hda_intel, chip);
- flush_work(&hda->probe_work);
+ cancel_work_sync(&hda->probe_work);
snd_card_free(card);
}