Re: Concurrent access to /dev/urandom

Jan Engelhardt
2004-11-27T21:22:11Z

>As shown in the code included in my first e-mail, each thread simply
>open("/dev/urandom", O_RDONLY), use read(2) to read 16 bytes, and
>then close the file descriptor.
>Duplicates appear quickly on: single CPU with HT, dual CPU without HT,
>and dual CPU with HT (all with smp kernels)
>But not on a lower end single CPU without HT (2.6.8-1.521 non-smp).

Ok, so it is a case of two "kernel-side" CPUs.

>> Rule of thumb: Post the smallest possible code that shows the problem.
>Will do next time!

That would be great, because it could show that urandom is missing a lock
somewhere.

Jan Engelhardt
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