Messages in this thread | | | Date | Thu, 7 Apr 2005 14:12:57 -0700 | From | Matt Mackall <> | Subject | Re: /dev/random problem on 2.6.12-rc1 |
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On Thu, Apr 07, 2005 at 05:36:59PM +0200, Simon Derr wrote: > > > On Thu, 7 Apr 2005, Yura Pakhuchiy wrote: > > > On Thu, 2005-04-07 at 14:40 +0200, Patrice Martinez wrote: > > > When using a machine with a 2612-rc 1kernel, I encounter problems > > > reading /dev/random: > > > it simply nevers returns anything, and the process is blocked in the > > > read... > > > The easiest way to see it is to type: > > > od < /dev/random > > > > > > Any idea? > > > > Because, /dev/random use user input, mouse movements and other things to > > generate next random number. Use /dev/urandom if you want version that > > will never block your machine. > > > > Read "man 4 random" for details. > > > Something changed since previous versions of the kernel, I guess. > Running `find /usr | wc' on a ssh session generates both network and disk > activity, and you should not expect any other kind of input on a networked > server.
FYI, network activity only generates entropy on a very small subset of NICs, and probably not the one you're using. This is good, as network activity is assumed passively observable/timable.
> Anyway, still zero bytes coming from /dev/random, for the few minutes I > waited.
Are you and Patrice both experiencing this on the same machine? What was the last kernel that was known to work for you? Do you see the contents of /proc/sys/kernel/random/entropy_avail change over time? Are there any other entropy consumers on your machine?
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