From: Paolo Abeni <pabeni@redhat.com>
To: Jakub Kicinski <kuba@kernel.org>, davem@davemloft.net
Cc: netdev@vger.kernel.org, edumazet@google.com,
andrew+netdev@lunn.ch, horms@kernel.org, shuah@kernel.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH net 04/12] net: shaper: try to avoid violating RCU
Date: Wed, 6 May 2026 17:22:01 +0200 [thread overview]
Message-ID: <59b26f1e-efd5-488e-8738-15e96b9c79e4@redhat.com> (raw)
In-Reply-To: <20260506000628.1501691-5-kuba@kernel.org>
On 5/6/26 2:06 AM, Jakub Kicinski wrote:
> net_shaper_commit() overrides nodes which may be concurrently read
> under RCU. This is not a huge deal since the entries only contain
> config, worst case user will see inconsistent config params. But
> we should try to avoid this obvious RCU violation. Try to allocate
> a new node. Since commit() can't fail fall back to overriding.
>
> Full fix is probably not worth the complexity, struct net_shaper
> is around 80B, and the allocation is with GFP_KERNEL.
I'm not sure if even this variant is worthy?!? The scheduler tree dump
could be still inconsistent, as the dump is not atomic. IMHO e.g.
inconsistent weights in the same WRR group would be as bad as
inconsistent values inside the single shaper.
/P
next prev parent reply other threads:[~2026-05-06 15:22 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-06 0:06 [PATCH net 00/12] net: shaper: fix various minor bugs Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 01/12] net: shaper: drop redundant xa_lock() bracketing Jakub Kicinski
2026-05-06 15:30 ` Paolo Abeni
2026-05-06 22:33 ` Jakub Kicinski
2026-05-07 7:10 ` Paolo Abeni
2026-05-06 0:06 ` [PATCH net 02/12] net: shaper: flip the polarity of the valid flag Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 03/12] net: shaper: fix trivial ordering issue in net_shaper_commit() Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 04/12] net: shaper: try to avoid violating RCU Jakub Kicinski
2026-05-06 15:22 ` Paolo Abeni [this message]
2026-05-06 15:32 ` Paolo Abeni
2026-05-06 22:35 ` Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 05/12] net: shaper: reject duplicate leaves in GROUP request Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 06/12] selftests: drv-net: add shaper test for duplicate leaves Jakub Kicinski
2026-05-06 16:40 ` Breno Leitao
2026-05-06 22:35 ` Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 07/12] net: shaper: set ret to -ENOMEM when genlmsg_new() fails in group_doit Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 08/12] net: shaper: fix undersized reply skb allocation in GROUP command Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 09/12] tools: ynl: add scope qualifier for definitions Jakub Kicinski
2026-05-06 2:32 ` Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 10/12] net: shaper: reject handle IDs exceeding internal bit-width Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 11/12] net: shaper: enforce singleton NETDEV scope with id 0 Jakub Kicinski
2026-05-06 0:06 ` [PATCH net 12/12] net: shaper: reject QUEUE scope handle with missing id Jakub Kicinski
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