valgrind reports memory leaks running:

.libs/cairo-test-suite -f dash-curve

>==5== 1,056 bytes in 3 blocks are definitely lost in loss record 1 of 9
>==5==    at 0x4A06BCF: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
>==5==    by 0x4CA9785: source.isra.4 (cairo/src/cairo-xlib-source.c:112)
>==5==    by 0x4CA9890: color_source (cairo/src/cairo-xlib-source.c:502)
>==5==    by 0x4CAAA7E: white_source (cairo/src/cairo-xlib-source.c:528)
>==5==    by 0x4CAAA7E: solid_source (cairo/src/cairo-xlib-source.c:607)
>==5==    by 0x4CAAA7E: _cairo_xlib_source_create_for_pattern (cairo/src/cairo-xlib-source.c:1128)
>==5==    by 0x4C90A6B: clip_and_composite (cairo/src/cairo-traps-compositor.c:1024)
>==5==    by 0x4C91ED6: clip_and_composite_traps (cairo/src/cairo-traps-compositor.c:1845)
>==5==
>==5== 1,056 bytes in 3 blocks are definitely lost in loss record 2 of 9
>==5==    at 0x4A06BCF: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
>==5==    by 0x4CA9785: source.isra.4 (cairo/src/cairo-xlib-source.c:112)
>==5==    by 0x4CA9890: color_source (cairo/src/cairo-xlib-source.c:502)
>==5==    by 0x4CAA36E: opaque_source (cairo/src/cairo-xlib-source.c:555)
>==5==    by 0x4CAA36E: solid_source (cairo/src/cairo-xlib-source.c:609)
>==5==
>==5== 7,072 bytes in 1 blocks are definitely lost in loss record 9 of 9
>==5==    at 0x4A06BCF: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
>==5==    by 0x4CAFEEB: _cairo_xlib_surface_put_shm (cairo/src/cairo-xlib-surface-shm.c:1107)
>==5==    by 0x4CAB858: _cairo_xlib_surface_flush (cairo/src/cairo-xlib-surface.c:1501)
>==5==    by 0x4C7E6CC: _cairo_surface_finish_snapshots (cairo/src/cairo-surface.c:1017)
>==5==    by 0x4C7E6CC: cairo_surface_destroy (cairo/src/cairo-surface.c:961)

In _cairo_xlib_display_destroy (src/cairo-xlib.c) the
cairo_surfaces:

display->white
display->alpha[0:255]
display->solid[0:16]

are not destroyed. And in _cairo_xlib_surface_put_shm and
_cairo_xlib_surface_update_shm (src/cairo-xlib-surface-shm.c)
'rects' is not freed when rects != stack_rects.