From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67D993A874A; Sat, 4 Apr 2026 09:50:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775296243; cv=none; b=UmYGN5kQCOCA7Vu0JrNNFaggToxfCxD4c+y2+8EAMxLUbCfzyg1SvfLHNZO0nRcKuDqkixLHMrYLIr5CADHuvDS2bVEHeLf4xMKm2BROQJjxf7byAHRpb7deGrawBeDpu+QJvkAn1jqtECNIH0dfv3HqKTPd2alRD3vMRf60z0g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775296243; c=relaxed/simple; bh=A7CUD0VUPo8ONzbdbm9INatuwjcxSlUhHVxYjU2jlvc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sMCuLdIamP2BOdKFgqMAeCgSOjPc4XBko09JmO6Z5abbO30d70SeytRlVx9qxloeh6PHAM9bmRHxt7ezG5vAgHg8iu87SQO5qVmgHhksdWn2ZmhuDNezfimjPCpvsQWVMDwtj8ro6YgXkV9/3psIZxTE0tYtXTYy4K1W6hff+tU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eYFKCUVt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eYFKCUVt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F40BEC19421; Sat, 4 Apr 2026 09:50:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775296243; bh=A7CUD0VUPo8ONzbdbm9INatuwjcxSlUhHVxYjU2jlvc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eYFKCUVt8h9gkcjFmXNR0rRq/JlszbgxYgrIzB11DsgxFKelANvaUm3I4zdNfqk/g unbocUPQ/OcleQMlqb92t8c8rCpM0xHax97omQaQHFQ2hqslSIeV/O003oTHkqbv+6 ASI/VY+EZPpeoeU32XQkoW36gmjvP04+E8T2BEQ/hoU8RF4/EThA89fzPqlc7XKy8T nW+4zLNM+gaY5p4oKGc2quA6O8LT9P7arYqChp8rAe4/fRlypmxqxXHxRMEU3bmZvN JO04y22uyW5RsQBZ7kYq0bdHB8DaBcPMGo1eLhdh6hBDuSxnGSOr8ozXMWTxjFgL9Q P3pyBQyMU9vig== Date: Sat, 4 Apr 2026 10:50:38 +0100 From: Simon Horman To: Stephen Hemminger Cc: netdev@vger.kernel.org, Jamal Hadi Salim , Jiri Pirko , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , =?utf-8?B?RnJhbsOnb2lz?= Michel , open list Subject: Re: [PATCH net v3 3/7] net/sched: netem: only reseed PRNG when seed is explicitly provided Message-ID: <20260404095038.GX113102@horms.kernel.org> References: <20260402202037.176299-1-stephen@networkplumber.org> <20260402202037.176299-4-stephen@networkplumber.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260402202037.176299-4-stephen@networkplumber.org> On Thu, Apr 02, 2026 at 01:19:31PM -0700, Stephen Hemminger wrote: > netem_change() unconditionally reseeds the PRNG on every tc change > command. If TCA_NETEM_PRNG_SEED is not specified, a new random seed > is generated, destroying reproducibility for users who set a > deterministic seed on a previous change. > > Move the initial random seed generation to netem_init() and only > reseed in netem_change() when TCA_NETEM_PRNG_SEED is explicitly > provided by the user. > > Fixes: 4072d97ddc44 ("netem: add prng attribute to netem_sched_data") > Signed-off-by: Stephen Hemminger Reviewed-by: Simon Horman