audio: Fix crash in a2dp_discover

Sample stack trace:
0x0000567c394e4c6b (bluetoothd - a2dp.c: 270) setup_cb_free
0x0000567c394e4a94 (bluetoothd - a2dp.c: 2884) a2dp_discover
0x0000567c394e3c03 (bluetoothd - sink.c: 275) sink_setup_stream
0x0000567c394e3d4f (bluetoothd - sink.c: 299) sink_connect
0x0000567c39535183 (bluetoothd - service.c: 294) btd_service_connect
0x0000567c39539f68 (bluetoothd - device.c: 2006) connect_next
0x0000567c3954086d (bluetoothd - device.c: 2060) service_state_changed
0x0000567c39534efb (bluetoothd - service.c: 111) change_state
0x0000567c3953559c (bluetoothd - service.c: 0)
btd_service_connecting_complete
0x0000567c39534a5c (bluetoothd - profile.c: 1641) record_cb
0x0000567c395197cd (bluetoothd - sdp-client.c: 298) connect_watch
0x00007b14bc8034f6 (libglib-2.0.so.0 - gmain.c: 3337)
g_main_context_dispatch
0x00007b14bc803801 (libglib-2.0.so.0 - gmain.c: 4131)
g_main_context_iterate
0x00007b14bc803a7d (libglib-2.0.so.0 - gmain.c: 4329) g_main_loop_run
0x0000567c39566af1 (bluetoothd - mainloop-glib.c: 79) mainloop_run
0x0000567c39566ddb (bluetoothd - mainloop-notify.c: 201)
mainloop_run_with_signal
0x0000567c3954bf4c (bluetoothd - main.c: 1222) main
0x00007b14bc579797 (libc.so.6 - libc-start.c: 332) __libc_start_main
0x0000567c394df449 (bluetoothd) _start
0x00007ffd70145737

This could be triggered from a2dp_discover -> avdtp_discover ->
send_request -> send_req -> l2cap_connect (return error) ->
avdtp_set_state (to disconnect state)-> channel_remove -> channel_free
-> finalize_setup_errno (discover cb is freed) -> error handling all
the way back to a2dp_discover -> a2dp_discover (discover cb is freed
again, crashed!).

The fix is to attach cb with setup after avdtp_discover success.

Suggested-by: luiz.dentz@gmail.com
Reviewed-by: Archie Pusaka <apusaka@chromium.org>
Signed-off-by: Manika Shrivastava <manika.sh@samsung.com>
Signed-off-by: Ayush Garg <ayush.garg@samsung.com>

diff --git a/profiles/audio/a2dp.c b/profiles/audio/a2dp.c
index 6cc28a0..10f2cd7 100644 (file)
--- a/profiles/audio/a2dp.c
+++ b/profiles/audio/a2dp.c
@@ -252,6 +252,15 @@ static struct a2dp_setup_cb *setup_cb_new(struct a2dp_setup *setup)
        cb->setup = setup;
        cb->id = ++cb_id;
 
+       return cb;
+}
+
+static struct a2dp_setup_cb *setup_cb_add(struct a2dp_setup *setup)
+{
+       struct a2dp_setup_cb *cb;
+
+       cb = setup_cb_new(setup);
+
        setup->cb = g_slist_append(setup->cb, cb);
        return cb;
 }
@@ -1943,7 +1952,7 @@ static int a2dp_reconfig(struct a2dp_channel *chan, const char *sender,
        if (!setup)
                return -ENOMEM;
 
-       cb_data = setup_cb_new(setup);
+       cb_data = setup_cb_add(setup);
        cb_data->config_cb = reconfig_cb;
        cb_data->user_data = user_data;
 
@@ -3079,12 +3088,17 @@ unsigned int a2dp_discover(struct avdtp *session, a2dp_discover_cb_t cb,
        if (!setup)
                return 0;
 
+       /* Don't add cb since avdtp_discover can end up disconnecting the
+        * session causing the cb to be freed.
+        */
        cb_data = setup_cb_new(setup);
        cb_data->discover_cb = cb;
        cb_data->user_data = user_data;
 
-       if (avdtp_discover(session, discover_cb, setup) == 0)
+       if (avdtp_discover(session, discover_cb, setup) == 0) {
+               setup->cb = g_slist_append(setup->cb, cb_data);
                return cb_data->id;
+       }
 
        setup_cb_free(cb_data);
        return 0;
@@ -3112,7 +3126,7 @@ unsigned int a2dp_select_capabilities(struct avdtp *session,
        if (!setup)
                return 0;
 
-       cb_data = setup_cb_new(setup);
+       cb_data = setup_cb_add(setup);
        cb_data->select_cb = cb;
        cb_data->user_data = user_data;
 
@@ -3185,7 +3199,7 @@ unsigned int a2dp_config(struct avdtp *session, struct a2dp_sep *sep,
        if (!setup)
                return 0;
 
-       cb_data = setup_cb_new(setup);
+       cb_data = setup_cb_add(setup);
        cb_data->config_cb = cb;
        cb_data->user_data = user_data;
 
@@ -3276,7 +3290,7 @@ unsigned int a2dp_resume(struct avdtp *session, struct a2dp_sep *sep,
        if (!setup)
                return 0;
 
-       cb_data = setup_cb_new(setup);
+       cb_data = setup_cb_add(setup);
        cb_data->resume_cb = cb;
        cb_data->user_data = user_data;
 
@@ -3334,7 +3348,7 @@ unsigned int a2dp_suspend(struct avdtp *session, struct a2dp_sep *sep,
        if (!setup)
                return 0;
 
-       cb_data = setup_cb_new(setup);
+       cb_data = setup_cb_add(setup);
        cb_data->suspend_cb = cb;
        cb_data->user_data = user_data;