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>
#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)
}
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");
}