From: Stephen Hemminger <stephen@networkplumber.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH 00/12] netem: fixes, cleanup, and selftest
Date: Sat, 14 Mar 2026 08:39:33 -0700 [thread overview]
Message-ID: <20260314083933.060c1449@phoenix.local> (raw)
In-Reply-To: <20260314070902.4025c388@kernel.org>
On Sat, 14 Mar 2026 07:09:02 -0700
Jakub Kicinski <kuba@kernel.org> wrote:
> On Fri, 13 Mar 2026 14:15:00 -0700 Stephen Hemminger wrote:
> > The netem packet scheduler is widely used for network emulation but
> > has not gotten enough of my attention lately.
>
> There's a few tests in tdcs which need adjusting:
>
> # not ok 363 d34d - NETEM test qdisc duplication restriction in qdisc tree in netem_change root
> # Command exited with 0, expected 2
> #
> # not ok 364 b33f - NETEM test qdisc duplication restriction in qdisc tree in netem_change non-root
> # Command exited with 0, expected 2
> #
> # not ok 365 cafe - NETEM test qdisc duplication restriction in qdisc tree
> # Command exited with 0, expected 2
> #
> # not ok 366 1337 - NETEM test qdisc duplication restriction in qdisc tree across branches
> # Command exited with 0, expected 2
That make sense.
If you run the new test on unpatched kernel expect three failures.
$ sudo ./netem.sh
PASS: basic netem delay
PASS: basic netem duplicate 50%
PASS: basic netem loss 30%
PASS: basic netem corrupt 10%
PASS: basic netem reorder 25% gap 5
PASS: netem with pfifo child qdisc
PASS: HTB root, two netem leaves (no dup)
# tc rejected multi-netem tree (check_netem_in_tree bug)
FAIL: HTB root, one netem with dup, one without
PASS: HFSC root, netem child (CVE-2025-37890 topology)
PASS: HFSC root, netem child with duplicate
PASS: HFSC root, two classes each with netem
PASS: netem with TBF child (non-work-conserving)
PASS: HTB -> netem -> TBF chain
PASS: netem with SFQ child qdisc
PASS: netem duplicate 100% (stress)
PASS: netem duplicate 100% with zero delay
PASS: netem all impairments simultaneously
PASS: rapid qdisc add/change/delete cycling
PASS: netem limit 1 with duplication
PASS: netem slot configuration
PASS: netem rate limiting
# tc rejected multi-netem dup tree (check_netem_in_tree bug)
FAIL: HTB root, two netem leaves both duplicating
# nested netem rejected by kernel (check_netem_in_tree bug)
FAIL: nested netem (netem inside netem child)
Summary: 20 pass, 3 fail, 0 skip
next prev parent reply other threads:[~2026-03-14 15:39 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-13 21:15 [PATCH 00/12] netem: fixes, cleanup, and selftest Stephen Hemminger
2026-03-13 21:15 ` [PATCH 01/12] selftests: net: add netem qdisc test Stephen Hemminger
2026-03-13 21:15 ` [PATCH 02/12] Revert "net/sched: Restrict conditions for adding duplicating netems to qdisc tree" Stephen Hemminger
2026-03-13 21:15 ` [PATCH 03/12] net/sched: netem: add per-CPU recursion guard for duplication Stephen Hemminger
2026-03-14 19:29 ` William Liu
2026-03-15 16:06 ` Stephen Hemminger
2026-03-15 16:19 ` Jamal Hadi Salim
2026-03-15 17:18 ` Stephen Hemminger
2026-03-16 17:52 ` Jamal Hadi Salim
2026-03-13 21:15 ` [PATCH 04/12] net/sched: netem: restructure dequeue to avoid re-entrancy with child qdisc Stephen Hemminger
2026-03-13 21:15 ` [PATCH 05/12] net/sched: netem: fix probability gaps in 4-state loss model Stephen Hemminger
2026-03-13 21:15 ` [PATCH 06/12] net/sched: netem: fix slot delay calculation overflow Stephen Hemminger
2026-03-13 21:15 ` [PATCH 07/12] net/sched: netem: fix queue limit check to include reordered packets Stephen Hemminger
2026-03-13 21:15 ` [PATCH 08/12] net/sched: netem: null-terminate tfifo linear queue tail Stephen Hemminger
2026-03-13 21:15 ` [PATCH 09/12] net/sched: netem: only reseed PRNG when seed is explicitly provided Stephen Hemminger
2026-03-13 21:15 ` [PATCH 10/12] net/sched: netem: move state enums out of struct netem_sched_data Stephen Hemminger
2026-03-13 21:15 ` [PATCH 11/12] net/sched: netem: remove useless VERSION Stephen Hemminger
2026-03-13 21:15 ` [PATCH 12/12] net/sched: netem: replace pr_info with netlink extack error messages Stephen Hemminger
2026-03-14 14:09 ` [PATCH 00/12] netem: fixes, cleanup, and selftest Jakub Kicinski
2026-03-14 15:39 ` Stephen Hemminger [this message]
2026-03-14 15:51 ` Stephen Hemminger
2026-03-14 16:00 ` Jakub Kicinski
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