Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 54CF447A0DC; Thu, 20 Aug 2026 16:45:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787244315; cv=none; b=D3Vb5nC33zEBe4nJLlcSDCaQD08/Sljib90bEvKvngkK9M9Qi8nZFF2DK2EAr/NWUb5rbTdide9K3RNnz4CUxiQZ9TYGFxpiTq78j8KUfD/WnMA0ryA999BFE4W0JZlmS/r0+B4eae2RkzSknMe2JPUBig2VH1kke+XYvleMDmU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787244315; c=relaxed/simple; bh=lp260QVlvFPp2m2c97TTbfE4U/WT9WmXLY7sUVIZOPU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gsA21zCig3V2yYnhVYk9T0w6Fje+z1RPaHh+QH6N1r5Z1Jm8Gs0ATUy28tShkoyHtVh+3OYa45g5ryHwIrAYBnxvFLVIJylNZXjp6F/cgUR+XZcQ1VwdZbWFDsdRyP2cwD3EiLXp5popR1QIn7Zz51na68qiwpapzemjUj0pp50= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DRWNgDFU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DRWNgDFU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B55ED1F000E9; Thu, 20 Aug 2026 16:45:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787244314; bh=ZHrN5yexNCBrq0/PN9bC+nWL96sQheA4XxMsaorW/LI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DRWNgDFUD+C/S9N2KAPaADnukzLXN7jByw4QbLajs85P0/+rg/ptO1KSEhk3ZWvNc OO51NpcmkBbMMEaUmGMy4VHlEmDNzZQ7ZtfrpzUb3UOjFvneFf7umr7XYZW3IF25P+ finKKQA2uzOgDxtKyRWO8P7baOrtbllrvZ1LyTeQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vladimir Oltean , Bryam Vargas , Victor Nogueira , Jamal Hadi Salim , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 125/235] net/sched: sch_taprio: Replace direct dequeue call with peek and qdisc_dequeue_peeked Date: Thu, 20 Aug 2026 16:56:01 +0200 Message-ID: <20260820145220.232020823@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145216.426568665@linuxfoundation.org> References: <20260820145216.426568665@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bryam Vargas [ Upstream commit e056e1dfcddca877dd46d704e8ec9860cfc9ec44 ] When taprio's software path peeks a non-work-conserving child qdisc, the child stashes the peeked skb in its gso_skb; taprio_dequeue_from_txq() then takes the packet with a direct child ->dequeue() call, which ignores that stash, orphans the peeked skb and desyncs the child's qlen/backlog. With a qfq child this re-enters the child on an emptied list and dereferences NULL, panicking the kernel from softirq on ordinary egress. Take the packet through qdisc_dequeue_peeked(), as sch_red and sch_sfb now do. The helper returns the child's stashed skb first and is a no-op when there is none, so a work-conserving child is unaffected and the gated path now consumes the skb whose length was charged to the budget. Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler") Cc: stable@vger.kernel.org Cc: Vladimir Oltean Signed-off-by: Bryam Vargas Reviewed-by: Victor Nogueira Acked-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260625-b4-disp-31bcb279-v1-1-85c40b83c529@proton.me Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_taprio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -588,7 +588,7 @@ static struct sk_buff *taprio_dequeue_fr return NULL; skip_peek_checks: - skb = child->ops->dequeue(child); + skb = qdisc_dequeue_peeked(child); if (unlikely(!skb)) return NULL;