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[94.209.165.62]) by smtp.gmail.com with ESMTPSA id a27sm4185928ejb.67.2020.10.25.09.27.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 25 Oct 2020 09:27:43 -0700 (PDT) From: Marijn Suijten To: linux-bluetooth@vger.kernel.org Cc: luiz.dentz@gmail.com, pali@kernel.org, Marijn Suijten Subject: [PATCH BlueZ] audio/a2dp: a2dp_channel should have a refcount on avdtp session Date: Sun, 25 Oct 2020 17:27:30 +0100 Message-Id: <20201025162730.47247-1-marijns95@gmail.com> X-Mailer: git-send-email 2.29.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org a2dp_channel keeps a reference to an avdtp session without incrementing its refcount. Not only does this appear wrong, it causes unexpected disconnections when the remote SEP responds with rejections. During testing with an audio application disconnections are observed when a codec config change through MediaEndpoint1.SetConfiguration fails. As soon as BlueZ receives this failure from the peer the corresponding a2dp_setup object is cleaned up which holds the last refcount to an avdtp session, in turn starting the disconnect process. An eventual open sink/source and transport have already closed by that time and released their refcounts. Adding refcounting semantics around a2dp_channel resolves the disconnections and allows future calls on MediaEndpoint1 to safely access the sesion stored within this channel. --- profiles/audio/a2dp.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/profiles/audio/a2dp.c b/profiles/audio/a2dp.c index cc4866b5b..0eac0135f 100644 --- a/profiles/audio/a2dp.c +++ b/profiles/audio/a2dp.c @@ -1507,6 +1507,9 @@ static void channel_free(void *data) avdtp_remove_state_cb(chan->state_id); + if (chan->session) + avdtp_unref(chan->session); + queue_destroy(chan->seps, remove_remote_sep); free(chan->last_used); g_free(chan); @@ -2065,7 +2068,7 @@ static void avdtp_state_cb(struct btd_device *dev, struct avdtp *session, break; case AVDTP_SESSION_STATE_CONNECTED: if (!chan->session) - chan->session = session; + chan->session = avdtp_ref(session); load_remote_seps(chan); break; } @@ -2145,6 +2148,7 @@ found: channel_remove(chan); return NULL; } + avdtp_ref(chan->session); return avdtp_ref(chan->session); } @@ -2165,6 +2169,7 @@ static void connect_cb(GIOChannel *io, GError *err, gpointer user_data) error("Unable to create AVDTP session"); goto fail; } + avdtp_ref(chan->session); } g_io_channel_unref(chan->io);