init: call time_init() before rand_initialize()

commit fe222a6ca2d53c38433cba5d3be62a39099e708e upstream.

Currently time_init() is called after rand_initialize(), but
rand_initialize() makes use of the timer on various platforms, and
sometimes this timer needs to be initialized by time_init() first. In
order for random_get_entropy() to not return zero during early boot when
it's potentially used as an entropy source, reverse the order of these
two calls. The block doing random initialization was right before
time_init() before, so changing the order shouldn't have any complicated
effects.

Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/init/main.c b/init/main.c
index 06b9835..2b9ba7e 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -1041,11 +1041,13 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
        softirq_init();
        timekeeping_init();
        kfence_init();
+       time_init();
 
        /*
         * For best initial stack canary entropy, prepare it after:
         * - setup_arch() for any UEFI RNG entropy and boot cmdline access
         * - timekeeping_init() for ktime entropy used in rand_initialize()
+        * - time_init() for making random_get_entropy() work on some platforms
         * - rand_initialize() to get any arch-specific entropy like RDRAND
         * - add_latent_entropy() to get any latent entropy
         * - adding command line entropy
@@ -1055,7 +1057,6 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
        add_device_randomness(command_line, strlen(command_line));
        boot_init_stack_canary();
 
-       time_init();
        perf_event_init();
        profile_init();
        call_function_init();