bpfloader/bpfloader.rc

service bpfloader /system/bin/bpfloader
    class main
    capabilities CHOWN SYS_ADMIN
    #
    # Set RLIMIT_MEMLOCK to 1GiB for bpfloader
    #
    # Actually only 8MiB would be needed if bpfloader ran as its own uid.
    #
    # However, while the rlimit is per-thread, the accounting is system wide.
    # So, for example, if the graphics stack has already allocated 10MiB of
    # memlock data before bpfloader even gets a chance to run, it would fail
    # if its memlock rlimit is only 8MiB - since there would be none left for it.
    #
    # bpfloader succeeding is critical to system health, since a failure will
    # cause netd crashloop and thus system server crashloop... and the only
    # recovery is a full kernel reboot.
    #
    # We've had issues where devices would sometimes (rarely) boot into
    # a crashloop because bpfloader would occasionally lose a boot time
    # race against the graphics stack's boot time locked memory allocation.
    #
    # Thus bpfloader's memlock has to be 8MB higher then the locked memory
    # consumption of the root uid anywhere else in the system...
    # But we don't know what that is for all possible devices...
    #
    # Ideally, we'd simply grant bpfloader the IPC_LOCK capability and it
    # would simply ignore it's memlock rlimit... but it turns that this
    # capability is not even checked by the kernel's bpf system call.
    #
    # As such we simply use 1GiB as a reasonable approximation of infinity.
    #
    rlimit memlock 1073741824 1073741824
    oneshot

# Need to make sure this runs *before* the bpfloader.
on early-init
    # Enable the eBPF JIT -- but do note that it is likely already force enabled
    # by the kernel config option BPF_JIT_ALWAYS_ON
    write /proc/sys/net/core/bpf_jit_enable 1
    # Enable JIT kallsyms export for privileged users only
    write /proc/sys/net/core/bpf_jit_kallsyms 1