Running OpenWRT 18.06 RC2 on x86/x64 machine, there is strange message at the end of dmesg log after booting.
[ 176.262358] random: crng init done
[ 176.262665] random: 1 urandom warning(s) missed due to ratelimiting
Any idea what it could be?
Everything seems to be working fine.
Urandom needs some data to seed itself, try typing on the keyboard during boot give it more data
It's really curious (the "solution" I mean).
Welcome to the magic world of entropy
[ 0.037905] random: get_random_u32 called from bucket_table_alloc+0x1a4/0x1f8 with crng_init=0
[ 5.369145] random: procd: uninitialized urandom read (4 bytes read)
[ 9.282518] urandom-seed: Seeding with /etc/urandom.seed
[ 9.994960] random: ubusd: uninitialized urandom read (4 bytes read)
[ 10.005219] random: ubusd: uninitialized urandom read (4 bytes read)
[ 10.011859] random: ubusd: uninitialized urandom read (4 bytes read)
[ 11.759376] urandom_read: 5 callbacks suppressed
[ 11.759383] random: jshn: uninitialized urandom read (4 bytes read)
[ 24.762525] random: fast init done
[ 57.390892] random: crng init done
All this "improvements/changes" have been introduced in 4.14.XX Kernels?
Because I don't remember messages like that in older firmwares (Lede/OpenWRT 4.9.XXX).
You will see this messages also on 4.9, 4.4 and probably older kernel versions too.
Thanks @juppin I never realized about this messages before.
Lack of entropy is a real problem in embedded devices right after boot.
I think that the warning for urandom quality was added to the kernel some time ago, but the warning was modified just a few months ago: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/?h=v4.14.56&id=4e00b339e264802851aff8e73cde7d24b57b18ce and backport to 4.9: https://lkml.org/lkml/2018/4/30/895
You might read Randomness quality for some background on lack of entropy in Openwrt. I wrote there a brief summary of mitigation attempts in Openwrt in the last 5-6 years.