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Date:   Tue, 29 Mar 2022 11:38:49 -0400
From:   "Theodore Ts'o" <tytso@mit.edu>
To:     Eric Biggers <ebiggers@google.com>
Cc:     Sasha Levin <sashal@kernel.org>, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Dominik Brodowski <linux@dominikbrodowski.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
Subject: Re: [PATCH AUTOSEL 5.17 16/43] random: use computational hash for
 entropy extraction
Message-ID: <YkMoCe+uX6UxfaeM@mit.edu>
References: <20220328111828.1554086-1-sashal@kernel.org>
 <20220328111828.1554086-16-sashal@kernel.org>
 <YkH5mhYokPB87FtE@google.com>
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On Mon, Mar 28, 2022 at 06:08:26PM +0000, Eric Biggers wrote:
> On Mon, Mar 28, 2022 at 07:18:00AM -0400, Sasha Levin wrote:
> > From: "Jason A. Donenfeld" <Jason@zx2c4.com>
> > 
> > [ Upstream commit 6e8ec2552c7d13991148e551e3325a624d73fac6 ]
> > 
> 
> I don't think it's a good idea to start backporting random commits to random.c
> that weren't marked for stable.  There were a lot of changes in v5.18, and
> sometimes they relate to each other in subtle ways, so the individual commits
> aren't necessarily safe to pick.
> 
> IMO, you shouldn't backport any non-stable-Cc'ed commits to random.c unless
> Jason explicitly reviews the exact sequence of commits that you're backporting.

Especially this commit in general, which is making a fundamental
change in how we extract entropy.  We should be very careful about
taking such changes into stable; a release or two of additonal "soak"
time would be a good idea before these go into the LTS releases in particular.

     	      	     	  	       	  - Ted