ALSA: vmaster: Propagate slave error

In slave_update() of vmaster code ignores the error from the slave
get() callback and copies the values.  It's not only about the missing
error code but also that this may potentially lead to a leak of
uninitialized variables when the slave get() don't clear them.

This patch fixes slave_update() not to copy the potentially
uninitialized values when an error is returned from the slave get()
callback, and to propagate the error value properly.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
index 8632301489fa..b67de2bb06a2 100644
--- a/sound/core/vmaster.c
+++ b/sound/core/vmaster.c
@@ -68,10 +68,13 @@ static int slave_update(struct link_slave *slave)
                 return -ENOMEM;
         uctl->id = slave->slave.id;
         err = slave->slave.get(&slave->slave, uctl);
+        if (err < 0)
+                goto error;
         for (ch = 0; ch < slave->info.count; ch++)
                 slave->vals[ch] = uctl->value.integer.value[ch];
+ error:
         kfree(uctl);
-        return 0;
+        return err < 0 ? err : 0;
 }
 
 /* get the slave ctl info and save the initial values */