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SubjectRe: [ALSA] seq: resource leak fix and various code cleanups
Hi Takashi-san,

<quote sender="Takashi Iwai">
> At Tue, 7 Aug 2007 16:40:48 +0800,
> Eugene Teo wrote:
> >
> > This patch fixes:
> > 1) a resource leak (CID: 1817)
> > 2) various code cleanups
[...]
> > if (i >= SNDRV_SEQ_OSS_MAX_CLIENTS) {
> > snd_printk(KERN_ERR "too many applications\n");
> > - kfree(dp);
> > - return -ENOMEM;
> > + rc = -ENOMEM;
> > + goto _error;
>
> This seems wrong. It goes before initializing dp->queue = -1, so it
> screws up delete_seq_queue().

You are right. The initialisations should come first.

> > @@ -276,11 +281,13 @@ snd_seq_oss_open(struct file *file, int level)
> > return 0;
> >
> > _error:
> > - snd_seq_oss_synth_cleanup(dp);
> > - snd_seq_oss_midi_cleanup(dp);
> > - i = dp->queue;
> > + snd_seq_oss_writeq_delete(dp->writeq);
> > + snd_seq_oss_readq_delete(dp->readq);
> > + delete_seq_queue(dp->queue);
> > delete_port(dp);
> > - delete_seq_queue(i);
> > + snd_seq_oss_midi_cleanup(dp);
> > + snd_seq_oss_synth_cleanup(dp);
> > + kfree(dp);
>
> The order of these calls is important. Did you test it and confirm
> that it has no side effects?

Only snd_seq_oss_synth_cleanup() and snd_seq_oss_midi_cleanup() should
be in order. The rest of the cleanup functions do not depend on one
another. Thanks for your advice.

Here's my second try:

This patch fixes:
1) a resource leak (CID: 1817)
2) various code cleanups

Signed-off-by: Eugene Teo <eugeneteo@kernel.sg>
---
sound/core/seq/oss/seq_oss_init.c | 40 +++++++++++++++++++++--------------
sound/core/seq/oss/seq_oss_writeq.c | 6 +++-
2 files changed, 28 insertions(+), 18 deletions(-)
diff --git a/sound/core/seq/oss/seq_oss_init.c b/sound/core/seq/oss/seq_oss_init.c
index ca5a2ed..f26b751 100644
--- a/sound/core/seq/oss/seq_oss_init.c
+++ b/sound/core/seq/oss/seq_oss_init.c
@@ -176,29 +176,31 @@ snd_seq_oss_open(struct file *file, int level)
int i, rc;
struct seq_oss_devinfo *dp;

- if ((dp = kzalloc(sizeof(*dp), GFP_KERNEL)) == NULL) {
+ dp = kzalloc(sizeof(*dp), GFP_KERNEL);
+ if (!dp) {
snd_printk(KERN_ERR "can't malloc device info\n");
return -ENOMEM;
}
debug_printk(("oss_open: dp = %p\n", dp));

+ dp->cseq = system_client;
+ dp->port = -1;
+ dp->queue = -1;
+ dp->readq = NULL;
+ dp->writeq = NULL;
+
for (i = 0; i < SNDRV_SEQ_OSS_MAX_CLIENTS; i++) {
if (client_table[i] == NULL)
break;
}
+
+ dp->index = i;
if (i >= SNDRV_SEQ_OSS_MAX_CLIENTS) {
snd_printk(KERN_ERR "too many applications\n");
- kfree(dp);
- return -ENOMEM;
+ rc = -ENOMEM;
+ goto _error;
}

- dp->index = i;
- dp->cseq = system_client;
- dp->port = -1;
- dp->queue = -1;
- dp->readq = NULL;
- dp->writeq = NULL;
-
/* look up synth and midi devices */
snd_seq_oss_synth_setup(dp);
snd_seq_oss_midi_setup(dp);
@@ -211,14 +213,16 @@ snd_seq_oss_open(struct file *file, int level)

/* create port */
debug_printk(("create new port\n"));
- if ((rc = create_port(dp)) < 0) {
+ rc = create_port(dp);
+ if (rc < 0) {
snd_printk(KERN_ERR "can't create port\n");
goto _error;
}

/* allocate queue */
debug_printk(("allocate queue\n"));
- if ((rc = alloc_seq_queue(dp)) < 0)
+ rc = alloc_seq_queue(dp);
+ if (rc < 0)
goto _error;

/* set address */
@@ -235,7 +239,8 @@ snd_seq_oss_open(struct file *file, int level)
/* initialize read queue */
debug_printk(("initialize read queue\n"));
if (is_read_mode(dp->file_mode)) {
- if ((dp->readq = snd_seq_oss_readq_new(dp, maxqlen)) == NULL) {
+ dp->readq = snd_seq_oss_readq_new(dp, maxqlen);
+ if (dp->readq == NULL) {
rc = -ENOMEM;
goto _error;
}
@@ -253,7 +258,8 @@ snd_seq_oss_open(struct file *file, int level)

/* initialize timer */
debug_printk(("initialize timer\n"));
- if ((dp->timer = snd_seq_oss_timer_new(dp)) == NULL) {
+ dp->timer = snd_seq_oss_timer_new(dp);
+ if (dp->timer == NULL) {
snd_printk(KERN_ERR "can't alloc timer\n");
rc = -ENOMEM;
goto _error;
@@ -276,11 +282,13 @@ snd_seq_oss_open(struct file *file, int level)
return 0;

_error:
+ snd_seq_oss_writeq_delete(dp->writeq);
+ snd_seq_oss_readq_delete(dp->readq);
snd_seq_oss_synth_cleanup(dp);
snd_seq_oss_midi_cleanup(dp);
- i = dp->queue;
delete_port(dp);
- delete_seq_queue(i);
+ delete_seq_queue(dp->queue);
+ kfree(dp);

return rc;
}
diff --git a/sound/core/seq/oss/seq_oss_writeq.c b/sound/core/seq/oss/seq_oss_writeq.c
index 5c84956..2174248 100644
--- a/sound/core/seq/oss/seq_oss_writeq.c
+++ b/sound/core/seq/oss/seq_oss_writeq.c
@@ -63,8 +63,10 @@ snd_seq_oss_writeq_new(struct seq_oss_devinfo *dp, int maxlen)
void
snd_seq_oss_writeq_delete(struct seq_oss_writeq *q)
{
- snd_seq_oss_writeq_clear(q); /* to be sure */
- kfree(q);
+ if (q) {
+ snd_seq_oss_writeq_clear(q); /* to be sure */
+ kfree(q);
+ }
}


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