reproduce (this is a W=1 build):
        git checkout c42ba5a87bdccbca11403b7ca8bad1a57b833732
        b4 shazam https://lore.kernel.org/r/20251122-tonyk-robust_futex-v6-4-05fea005a0fd@igalia.com
        # apt-get install sparse
        # sparse version: v0.6.4-71-g610d841d

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=i386 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=i386 SHELL=/bin/bash kernel/futex/