From: Simon Horman <horms@kernel.org>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: netdev@vger.kernel.org, "Jamal Hadi Salim" <jhs@mojatatu.com>,
"Jiri Pirko" <jiri@resnulli.us>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"François Michel" <francois.michel@uclouvain.be>,
"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net v3 3/7] net/sched: netem: only reseed PRNG when seed is explicitly provided
Date: Sat, 4 Apr 2026 10:50:38 +0100 [thread overview]
Message-ID: <20260404095038.GX113102@horms.kernel.org> (raw)
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 <stephen@networkplumber.org>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2026-04-04 9:50 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-02 20:19 [PATCH net v3 0/7] net/sched: netem: bug fixes Stephen Hemminger
2026-04-02 20:19 ` [PATCH net v3 1/7] net/sched: netem: fix probability gaps in 4-state loss model Stephen Hemminger
2026-04-04 9:50 ` Simon Horman
2026-04-02 20:19 ` [PATCH net v3 2/7] net/sched: netem: fix queue limit check to include reordered packets Stephen Hemminger
2026-04-04 9:50 ` Simon Horman
2026-04-02 20:19 ` [PATCH net v3 3/7] net/sched: netem: only reseed PRNG when seed is explicitly provided Stephen Hemminger
2026-04-04 9:50 ` Simon Horman [this message]
2026-04-02 20:19 ` [PATCH net v3 4/7] net/sched: netem: restructure dequeue to avoid re-entrancy with child qdisc Stephen Hemminger
2026-04-04 9:49 ` Simon Horman
2026-04-06 15:41 ` Jakub Kicinski
2026-04-06 17:12 ` Stephen Hemminger
2026-04-02 20:19 ` [PATCH net v3 5/7] net/sched: netem: null-terminate tfifo linear queue tail Stephen Hemminger
2026-04-04 9:50 ` Simon Horman
2026-04-02 20:19 ` [PATCH net v3 6/7] net/sched: netem: check for invalid slot range Stephen Hemminger
2026-04-04 9:51 ` Simon Horman
2026-04-02 20:19 ` [PATCH net v3 7/7] net/sched: netem: fix slot delay calculation overflow Stephen Hemminger
2026-04-04 9:51 ` Simon Horman
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