[PATCH 2/2] hw/audio/hda: fix memory leak on audio setup

[Paolo Bonzini]

When SET_STREAM_FORMAT is called, the st->buft timer is overwritten, thus
causing a memory leak.  This was originally fixed in commit 816139ae6a5
("hw/audio/hda: fix memory leak on audio setup", 2024-11-14) but that
caused the audio to break in SPICE.

Fortunately, a simpler fix is possible.  The timer only needs to be
reset, because the callback is always the same (st->output is set at
realize time in hda_audio_init); call to timer_new_ns overkill.  Replace
it with timer_del and only initialize the timer once; for simplicity,
do it even if use_timer is false.

An even simpler fix would be to free the old time in hda_audio_setup().
However, it seems better to place the initialization of the timer close
to that of st->ouput.

Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/audio/hda-codec.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/hw/audio/hda-codec.c b/hw/audio/hda-codec.c
index 74c0292284e..c340a9481d5 100644
--- a/hw/audio/hda-codec.c
+++ b/hw/audio/hda-codec.c
@@ -487,8 +487,7 @@ static void hda_audio_setup(HDAAudioStream *st)
     if (st->output) {
         if (use_timer) {
             cb = hda_audio_output_cb;
-            st->buft = timer_new_ns(QEMU_CLOCK_VIRTUAL,
-                                    hda_audio_output_timer, st);
+            timer_del(st->buft);
         } else {
             cb = hda_audio_compat_output_cb;
         }
@@ -497,8 +496,7 @@ static void hda_audio_setup(HDAAudioStream *st)
     } else {
         if (use_timer) {
             cb = hda_audio_input_cb;
-            st->buft = timer_new_ns(QEMU_CLOCK_VIRTUAL,
-                                    hda_audio_input_timer, st);
+            timer_del(st->buft);
         } else {
             cb = hda_audio_compat_input_cb;
         }
@@ -726,8 +724,12 @@ static void hda_audio_init(HDACodecDevice *hda,
                 st->gain_right = QEMU_HDA_AMP_STEPS;
                 st->compat_bpos = sizeof(st->compat_buf);
                 st->output = true;
+                st->buft = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                                        hda_audio_output_timer, st);
             } else {
                 st->output = false;
+                st->buft = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                                        hda_audio_input_timer, st);
             }
             st->format = AC_FMT_TYPE_PCM | AC_FMT_BITS_16 |
                 (1 << AC_FMT_CHAN_SHIFT);
@@ -750,9 +752,7 @@ static void hda_audio_exit(HDACodecDevice *hda)
         if (st->node == NULL) {
             continue;
         }
-        if (a->use_timer) {
-            timer_free(st->buft);
-        }
+        timer_free(st->buft);
         if (st->output) {
             AUD_close_out(&a->card, st->voice.out);
         } else {
-- 
2.47.0