https://bugs.freedesktop.org/show_bug.cgi?id=60028
--- Comment #7 from Michel Dänzer michel@daenzer.net --- This is indeed more likely an issue in Mesa than in the kernel. The commit you bisected also bumps KMS_DRIVER_MINOR in radeon_drv.c, which may cause the Mesa code to use different code paths.
Does current Mesa Git still leak?