shm: Log a warning if a shm buffer address is requested when it may be invalid

If wl_shm_buffer_get_data() is called on a shm pool that has an external
reference and a pending resize, then the buffer may be outside the pool's
current mapping.

Log a warning if this happens.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

diff --git a/src/wayland-shm.c b/src/wayland-shm.c
index be3dd3f..5efbd70 100644 (file)
--- a/src/wayland-shm.c
+++ b/src/wayland-shm.c
@@ -387,6 +387,11 @@ wl_shm_buffer_get_data(struct wl_shm_buffer *buffer)
        if (!buffer->pool)
                return NULL;
 
+       if (buffer->pool->external_refcount &&
+           (buffer->pool->size != buffer->pool->new_size))
+               wl_log("Buffer address requested when its parent pool "
+                      "has an external reference and a deferred resize "
+                      "pending.\n");
        return buffer->pool->data + buffer->offset;
 }