Victor Nogueira e781122d76 net/sched: Abort __tc_modify_qdisc if parent is a clsact/ingress qdisc
Wang reported an illegal configuration [1] where the user attempts to add a
child qdisc to the ingress qdisc as follows:

tc qdisc add dev eth0 handle ffff:0 ingress
tc qdisc add dev eth0 handle ffe0:0 parent ffff:a fq

To solve this, we reject any configuration attempt to add a child qdisc to
ingress or clsact.

[1] https://lore.kernel.org/netdev/20251105022213.1981982-1-wangliang74@huawei.com/

Fixes: 5e50da01d0 ("[NET_SCHED]: Fix endless loops (part 2): "simple" qdiscs")
Reported-by: Wang Liang <wangliang74@huawei.com>
Closes: https://lore.kernel.org/netdev/20251105022213.1981982-1-wangliang74@huawei.com/
Reviewed-by: Pedro Tammela <pctammela@mojatatu.ai>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Reviewed-by: Cong Wang <cwang@multikernel.io>
Link: https://patch.msgid.link/20251106205621.3307639-1-victor@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-10 16:57:56 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-11-02 11:28:02 -08:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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