dsp: audio_ion: add lock for msm_audio_ion_crash_handler

msm_audio_fd_data can be freed in msm_audio_delete_fd_entry and
msm_audio_ion_crash_handler.Add lock for msm_audio_ion_crash_handler
to avoid race condition during removal of msm_audio_fd_data and dereference.

Change-Id: I49dc0a1aca45ffad76b39e06fe075185d4281d00
Signed-off-by: Meng Wang <[email protected]>

dsp/msm_audio_ion.c

@@ -572,6 +572,7 @@ void msm_audio_ion_crash_handler(void)
 	struct msm_audio_ion_private *ion_data = NULL;
 
 	pr_debug("Inside %s\n", __func__);
+	mutex_lock(&(msm_audio_ion_fd_list.list_mutex));
 	list_for_each_entry(msm_audio_fd_data,
 		&msm_audio_ion_fd_list.fd_list, list) {
 		handle = msm_audio_fd_data->handle;
@@ -585,6 +586,7 @@ void msm_audio_ion_crash_handler(void)
 		list_del(&(msm_audio_fd_data->list));
 		kfree(msm_audio_fd_data);
 	}
+	mutex_unlock(&(msm_audio_ion_fd_list.list_mutex));
 }
 EXPORT_SYMBOL(msm_audio_ion_crash_handler);