From: Simon Horman <horms@kernel.org>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: netdev@vger.kernel.org, jiri@resnulli.us, jhs@mojatatu.com,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Martin Ottens <martin.ottens@fau.de>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net v8 2/6] net/sched: netem: fix queue limit check to include reordered packets
Date: Tue, 21 Apr 2026 14:15:00 +0100 [thread overview]
Message-ID: <20260421131500.GB651125@horms.kernel.org> (raw)
In-Reply-To: <20260418032027.900913-3-stephen@networkplumber.org>
On Fri, Apr 17, 2026 at 08:19:40PM -0700, Stephen Hemminger wrote:
> The queue limit check in netem_enqueue() uses q->t_len which only
> counts packets in the internal tfifo. Packets placed in sch->q by
> the reorder path (__qdisc_enqueue_head) are not counted, allowing
> the total queue occupancy to exceed sch->limit under reordering.
>
> Include sch->q.qlen in the limit check.
>
> Fixes: f8d4bc455047 ("net/sched: netem: account for backlog updates from child qdisc")
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> Reviewed-by: Simon Horman <horms@kernel.org>
I acknowledge that Sashiko has provided review of this patch.
In the case of the commentary on the use of sch->q.qlen in place of q->t_len:
this is exactly the intention of this patch; to address shortcomings
in commit f8d4bc455047. Follow-up issues can be treated as such.
In the case of feedback on us of qdisc_drop_all(): if this is a problem
then it predates this patch and can be addressed separately to this
patch-set.
...
next prev parent reply other threads:[~2026-04-21 13:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-18 3:19 [PATCH v8 net 0/6] netem: bug fixes Stephen Hemminger
2026-04-18 3:19 ` [PATCH net v8 1/6] net/sched: netem: fix probability gaps in 4-state loss model Stephen Hemminger
2026-04-18 3:19 ` [PATCH net v8 2/6] net/sched: netem: fix queue limit check to include reordered packets Stephen Hemminger
2026-04-21 13:15 ` Simon Horman [this message]
2026-04-18 3:19 ` [PATCH net v8 3/6] net/sched: netem: only reseed PRNG when seed is explicitly provided Stephen Hemminger
2026-04-18 3:19 ` [PATCH net v8 4/6] net/sched: netem: validate slot configuration Stephen Hemminger
2026-04-21 13:10 ` Simon Horman
2026-04-18 3:19 ` [PATCH net v8 5/6] net/sched: netem: fix slot delay calculation overflow Stephen Hemminger
2026-04-18 3:19 ` [PATCH net v8 6/6] net/sched: netem: check for negative latency and jitter Stephen Hemminger
2026-04-21 13:16 ` Simon Horman
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=20260421131500.GB651125@horms.kernel.org \
--to=horms@kernel.org \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=jhs@mojatatu.com \
--cc=jiri@resnulli.us \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=martin.ottens@fau.de \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=stephen@networkplumber.org \
/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