From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Thiago Macieira <thiago.macieira@intel.com>
Cc: Borislav Petkov <bp@alien8.de>,
Christopher Snowhill <chris@kode54.net>,
Gregory Price <gourry@gourry.net>,
x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com,
peterz@infradead.org, mario.limonciello@amd.com,
riel@surriel.com, yazen.ghannam@amd.com, me@mixaill.net,
kai.huang@intel.com, sandipan.das@amd.com, darwi@linutronix.de,
stable@vger.kernel.org
Subject: Re: [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error.
Date: Sat, 8 Nov 2025 00:07:13 +0100 [thread overview]
Message-ID: <aQ57ofElS-N0gEco@zx2c4.com> (raw)
In-Reply-To: <2790505.9o76ZdvQCi@tjmaciei-mobl5>
Hi Thiago,
On Fri, Nov 07, 2025 at 11:55:35AM -0800, Thiago Macieira wrote:
> I'm not asking about the performance of generating new random numbers in this
> process.
>
> I am asking about the system-wide impact that draining the entropy source
> would have. Is that a bad thing?
>
> I suspect the answer is "no" because it's the same as /dev/urandom anyway.
Oh. "Entropy source draining" is not a real thing. There used to be
bizarre behavior related to /dev/random (not urandom), but this has been
gone for ages. And even the non-getrandom Linux fallback code uses
/dev/urandom before /dev/random. So not even on old kernels is this an
issue. You can keep generating random numbers forever without worrying
about running out of juice or irritating other processes.
Jason
next prev parent reply other threads:[~2025-11-07 23:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-18 2:40 [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error Gregory Price
2025-10-18 10:03 ` Borislav Petkov
2025-10-19 14:46 ` Jason A. Donenfeld
2025-10-19 15:00 ` Borislav Petkov
2025-10-19 15:03 ` Jason A. Donenfeld
2025-11-03 10:22 ` Christopher Snowhill
2025-11-03 12:03 ` Borislav Petkov
2025-11-03 23:55 ` Christopher Snowhill
2025-11-04 13:21 ` Borislav Petkov
2025-11-04 14:28 ` Jason A. Donenfeld
2025-11-04 15:00 ` Jason A. Donenfeld
2025-11-04 18:08 ` Thiago Macieira
2025-11-04 21:56 ` Jason A. Donenfeld
2025-11-04 23:50 ` Thiago Macieira
2025-11-05 1:58 ` Jason A. Donenfeld
2025-11-05 16:41 ` Thiago Macieira
2025-11-07 19:13 ` Jason A. Donenfeld
2025-11-07 19:55 ` Thiago Macieira
2025-11-07 23:07 ` Jason A. Donenfeld [this message]
2025-11-07 23:11 ` Thiago Macieira
2025-11-08 0:04 ` Jason A. Donenfeld
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aQ57ofElS-N0gEco@zx2c4.com \
--to=jason@zx2c4.com \
--cc=bp@alien8.de \
--cc=chris@kode54.net \
--cc=darwi@linutronix.de \
--cc=dave.hansen@linux.intel.com \
--cc=gourry@gourry.net \
--cc=hpa@zytor.com \
--cc=kai.huang@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mario.limonciello@amd.com \
--cc=me@mixaill.net \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=riel@surriel.com \
--cc=sandipan.das@amd.com \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=thiago.macieira@intel.com \
--cc=x86@kernel.org \
--cc=yazen.ghannam@amd.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox