14.3.29. The appWeb
server hangs OR /dev/random hangs
- Question:
- I try to run the
appWeb
server, but it hangs, because read accesses to/dev/random
hang forever. What's wrong?
- Answer:
- Your configuration of the Linux kernel does not contain drivers
that feed enough entropy for
/dev/random
. Often mouse or keyboard drivers are used for this purpose, so on an embedded system without such devices/dev/random
may not provide enough random numbers for your application.
- Workaround:
- As a quick workaround you can use
/dev/urandom
instead; i. e. try the following commands on your system:# cd /dev # rm -f random # ln -s urandom random
- Solution:
- The correct solution for the problem is of course to feed
sufficient entropy into
/dev/random
. To do so you can modify one or more appropriate device drivers on your system; for example if you know that there is sufficient traffic on network or on a serial port than addingSA_SAMPLE_RANDOM
to the 3rd argument when calling therequest_irq()
function in your ethernet and/or serial driver(s) will cause the inter-interrupt times to be used to build up entropy for/dev/random
.
14.3.28. How can I access U-Boot environment variables in Linux? | 1. Abstract | 14.3.30. Swapping over NFS | |||
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