From: "Jason A. Donenfeld" Jason@zx2c4.com
[ Upstream commit fe222a6ca2d53c38433cba5d3be62a39099e708e ]
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: Sasha Levin sashal@kernel.org --- init/main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/init/main.c b/init/main.c index 9a5097b2251a..b18aa5d19038 100644 --- a/init/main.c +++ b/init/main.c @@ -1035,11 +1035,13 @@ 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 @@ -1049,7 +1051,6 @@ 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();