On Fri, 26 May 2023 13:24:04 -0700
stan via kernel <kernel(a)lists.fedoraproject.org> wrote:
On Fri, 26 May 2023 12:36:18 -0700
stan via kernel <kernel(a)lists.fedoraproject.org> wrote:
> I compile a custom kernel (currently 6.4 rc1), and I have
> CONFIG_PROC_SYSCTL=y
> set in the configuration. I run a program that gathers entropy from
> the atmosphere and feeds it into the kernel entropy pool via the
> public kernel interface. When I start the program, I want to change
> the thresholds for entropy because there is no longer any shortage
> of entropy, so I want it to be kept full (4096). I do that using
> /usr/bin/echo 3967 > /proc/sys/kernel/random/write_wakeup_threshold
> I haven't checked in a while using
> cat /proc/sys/kernel/random/entropy_avail
> It used to hover around 4030 or so. But now the
> write_wakeup_threshold is 256, and the amount of entropy is 256, and
> no changes are possible.
>
> Have there been recent changes to the kernel random generation
> process? Has this been deprecated or restricted?
It seems that this is a known issue, and I am not the only one
affected. It is
discussed in the link
below.
https://github.com/nhorman/rng-tools/issues/173
I see this from the author of LRNG.
"The following patch set provides a different approach to /dev/random
which is called Linux Random Number Generator (LRNG) to collect entropy
within the Linux kernel. It provides the same API and ABI and can be
used as a drop-in replacement."
Obviously, the last sentence is false, since it caused the user input
of entropy to the kernel to fail, because it changed the process.
It removed the two proc/sys values as having any relevance. I'll have
to see if I can ditch this LRNG since I don't need it, and from the
thread above, it doesn't seem like it will work for individuals wanting
to add entropy.
I completely missed any discussion of this. It's too bad the author
didn't add it in a way that didn't interfere with existing
functionality.