diff --git a/drivers/char/random.c b/drivers/char/random.c index 2a41b21623ae42b6efdf530287c5f7e20660e3a1..d20ba1b104ca3aceadd19fb6fbcb9ba035799a62 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1277,6 +1277,7 @@ void add_interrupt_randomness(int irq, int irq_flags) fast_mix(fast_pool); add_interrupt_bench(cycles); + this_cpu_add(net_rand_state.s1, fast_pool->pool[cycles & 3]); if (unlikely(crng_init == 0)) { if ((fast_pool->count >= 64) && diff --git a/include/linux/random.h b/include/linux/random.h index 45e1f8fa742bcdaec079e7e64999ece155f01385..39aaa1f78f9ddeb26058a1147157c5b4e03f31e6 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -11,6 +11,7 @@ #include <linux/kernel.h> #include <linux/list.h> #include <linux/once.h> +#include <linux/percpu.h> #include <uapi/linux/random.h> @@ -119,6 +120,8 @@ struct rnd_state { __u32 s1, s2, s3, s4; }; +DECLARE_PER_CPU(struct rnd_state, net_rand_state) __latent_entropy; + u32 prandom_u32_state(struct rnd_state *state); void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes); void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state); diff --git a/kernel/time/timer.c b/kernel/time/timer.c index df1ff803acc4ff1338c535b58e2b78e160a8d308..026ac01af9da7e7619ec365e1efbdd638c0b2695 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -43,6 +43,7 @@ #include <linux/sched/debug.h> #include <linux/slab.h> #include <linux/compat.h> +#include <linux/random.h> #include <linux/uaccess.h> #include <asm/unistd.h> @@ -1742,6 +1743,13 @@ void update_process_times(int user_tick) scheduler_tick(); if (IS_ENABLED(CONFIG_POSIX_TIMERS)) run_posix_cpu_timers(); + + /* The current CPU might make use of net randoms without receiving IRQs + * to renew them often enough. Let's update the net_rand_state from a + * non-constant value that's not affine to the number of calls to make + * sure it's updated when there's some activity (we don't care in idle). + */ + this_cpu_add(net_rand_state.s1, rol32(jiffies, 24) + user_tick); } /** diff --git a/lib/random32.c b/lib/random32.c index 763b920a6206cd6ffc4cd9668885223f2d6a2790..c4d317be2997b5096b9cd68b281726a23c368323 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -48,7 +48,7 @@ static inline void prandom_state_selftest(void) } #endif -static DEFINE_PER_CPU(struct rnd_state, net_rand_state) __latent_entropy; +DEFINE_PER_CPU(struct rnd_state, net_rand_state) __latent_entropy; /** * prandom_u32_state - seeded pseudo-random number generator.