net/sched: sch_qfq: Fix race condition on qfq_aggregate

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[ Upstream commit 5e28d5a3f7 ]

A race condition can occur when 'agg' is modified in qfq_change_agg
(called during qfq_enqueue) while other threads access it
concurrently. For example, qfq_dump_class may trigger a NULL
dereference, and qfq_delete_class may cause a use-after-free.

This patch addresses the issue by:

1. Moved qfq_destroy_class into the critical section.

2. Added sch_tree_lock protection to qfq_dump_class and
qfq_dump_class_stats.

Fixes: 462dbc9101 ("pkt_sched: QFQ Plus: fair-queueing service at DRR cost")
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

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Xiang Mei 2025-07-10 03:09:42 -07:00 • committed by Greg Kroah-Hartman

parent d24d34c4ec

commit 466e10194a

1 changed files with 21 additions and 9 deletions

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net/sched/sch_qfq.c

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