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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2021-12-29 22:10:04 +0100 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-01-07 00:25:25 +0100 |
| commit | 9c3ddde3f811aabbb83778a2a615bf141b4909ef (patch) | |
| tree | dc82807a0f89434a8675ddadd9b41dd0b2e3c021 /drivers/char | |
| parent | f7e67b8e803185d0aabe7f29d25a35c8be724a78 (diff) | |
| download | lwn-9c3ddde3f811aabbb83778a2a615bf141b4909ef.tar.gz lwn-9c3ddde3f811aabbb83778a2a615bf141b4909ef.zip | |
random: do not re-init if crng_reseed completes before primary init
If the bootloader supplies sufficient material and crng_reseed() is called
very early on, but not too early that wqs aren't available yet, then we
might transition to crng_init==2 before rand_initialize()'s call to
crng_initialize_primary() made. Then, when crng_initialize_primary() is
called, if we're trusting the CPU's RDRAND instructions, we'll
needlessly reinitialize the RNG and emit a message about it. This is
mostly harmless, as numa_crng_init() will allocate and then free what it
just allocated, and excessive calls to invalidate_batched_entropy()
aren't so harmful. But it is funky and the extra message is confusing,
so avoid the re-initialization all together by checking for crng_init <
2 in crng_initialize_primary(), just as we already do in crng_reseed().
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 144e8841bff4..916cf791ed0e 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -827,7 +827,7 @@ static void __init crng_initialize_primary(struct crng_state *crng) { chacha_init_consts(crng->state); _extract_entropy(&input_pool, &crng->state[4], sizeof(__u32) * 12, 0); - if (crng_init_try_arch_early(crng) && trust_cpu) { + if (crng_init_try_arch_early(crng) && trust_cpu && crng_init < 2) { invalidate_batched_entropy(); numa_crng_init(); crng_init = 2; |