[ Upstream commit fe6f1a6a8eedc1aa538fee0baa612b6a59639cf8 ]
When the system boots with random.trust_cpu=1 it doesn't initialize the per-NUMA CRNGs because it skips the rest of the CRNG startup code. This means that the code from 1e7f583af67b ("random: make /dev/urandom scalable for silly userspace programs") is not used when random.trust_cpu=1.
crash> dmesg | grep random: [ 0.000000] random: get_random_bytes called from start_kernel+0x94/0x530 with crng_init=0 [ 0.314029] random: crng done (trusting CPU's manufacturer) crash> print crng_node_pool $6 = (struct crng_state **) 0x0
After adding the missing call to numa_crng_init() the per-NUMA CRNGs are initialized again:
crash> dmesg | grep random: [ 0.000000] random: get_random_bytes called from start_kernel+0x94/0x530 with crng_init=0 [ 0.314031] random: crng done (trusting CPU's manufacturer) crash> print crng_node_pool $1 = (struct crng_state **) 0xffff9a915f4014a0
The call to invalidate_batched_entropy() was also missing. This is important for architectures like PPC and S390 which only have the arch_get_random_seed_* functions.
Fixes: 39a8883a2b98 ("random: add a config option to trust the CPU's hwrng") Signed-off-by: Jon DeVree nuxi@vault24.org Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/char/random.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c index 38c6d1af6d1c0..d4d45ccfeefc0 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -777,6 +777,7 @@ static struct crng_state **crng_node_pool __read_mostly; #endif
static void invalidate_batched_entropy(void); +static void numa_crng_init(void);
static bool trust_cpu __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU); static int __init parse_trust_cpu(char *arg) @@ -805,7 +806,9 @@ static void crng_initialize(struct crng_state *crng) } crng->state[i] ^= rv; } - if (trust_cpu && arch_init) { + if (trust_cpu && arch_init && crng == &primary_crng) { + invalidate_batched_entropy(); + numa_crng_init(); crng_init = 2; pr_notice("random: crng done (trusting CPU's manufacturer)\n"); }