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LIN7-6928 : CLONE - KNOWLEDGE FORUM - Question : urandom startup order changed in WRL6 RCPL30

Created: Oct 20, 2016    Updated: Sep 8, 2018
Resolved Date: Oct 20, 2016
Previous ID: LIN6-11869
Found In Version:
Fix Version:
Severity: Severe
Applicable for: Wind River Linux 7
Component/s: Userspace


The random number generator gathers environmental noise from device drivers and other sources into an entropy pool. The generator also keeps an estimate of the number of bits of noise in the entropy pool. From this entropy pool random numbers are created.

When a Linux system starts up without much operator interaction, the entropy pool may be in a fairly predictable state. This reduces the actual amount of noise in the entropy pool below the estimate. 

In order to counteract this effect, it helps to carry entropy pool information across shut-downs and start-ups.

LIN6-11019 has the effect to call much later "urandom start" in the boot process (at runlevel 3 step 30 instead of runlevel S step 30) results a initialized entropy pool much later.

LIN6-11019 also changes the order at shutdown of "urandom stop" to be earlier (from S30 to K70). 

Steps to Reproduce

Compare urandom service before and after LIN6-11019 patch by enabling "VERBOSE=yes" in /etc/default/rcS.

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