From mboxrd@z Thu Jan 1 00:00:00 1970 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 7CF1B348C55; Wed, 20 May 2026 18:19:14 +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=1779301155; cv=none; b=GAw+sSlOMR4vyJem6fdsSqxmnfq/ojgFoIuLxaiCbdfCIDRTwDfWmLEoql5ASVTCQQ3kmwUFY15374hmw01lLbS6BT8SngxIEIB57ergpa/bEiwxwFlJcco4PV6Zi0VgTiZy1YwS17myQVcfzdSJOVb1XChNEaoGPnWmKSglE2Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301155; c=relaxed/simple; bh=jGZiWMW3DNkpIYYFryY+pdimctF+4A1KQlQJlhJETBA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CfT+Nz/7hSDzNPTYh5BOK7a6W++3tizh1QAm/1wrPPKTgB6jASCwgCzFeGB/JPoNoV4o25cIIBKEE0N6LulnjI+0MzlErF4N+DFRVIPOd0Z5gmNZC48tLjYsZPjk4H8+s3g39yWMMJiS5XTuSXNn2mbI3iahvy2FVs88q6Zv1p0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JxW6xP9q; 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="JxW6xP9q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3AF91F000E9; Wed, 20 May 2026 18:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779301154; bh=OPnnePbhf69RHGTtSTVg3tzPk229FQp8KWxRteJySds=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JxW6xP9qzfwSHVBvtCwW8qDq7DhHW5ufhIK+Bfl6e8IkxUHOskyN0OMur3+eA7a5C nQDtGvD3bD1O6yxtutsXlADXNwaA9ZcWwCqHe3CXiACYPYhmLztlZKJZNXYVMOA+f9 Ss3kfACydbaJoLuA5ajITPSqQxMull4VZ8j6//Uk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Junxi Qian , Vinicius Costa Gomes , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 448/666] net/sched: taprio: fix use-after-free in advance_sched() on schedule switch Date: Wed, 20 May 2026 18:20:59 +0200 Message-ID: <20260520162120.981237660@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162111.222830634@linuxfoundation.org> References: <20260520162111.222830634@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vinicius Costa Gomes [ Upstream commit 105425b1969c5affe532713cfac1c0b320d7ac2b ] In advance_sched(), when should_change_schedules() returns true, switch_schedules() is called to promote the admin schedule to oper. switch_schedules() queues the old oper schedule for RCU freeing via call_rcu(), but 'next' still points into an entry of the old oper schedule. The subsequent 'next->end_time = end_time' and rcu_assign_pointer(q->current_entry, next) are use-after-free. Fix this by selecting 'next' from the new oper schedule immediately after switch_schedules(), and using its pre-calculated end_time. setup_first_end_time() sets the first entry's end_time to base_time + interval when the schedule is installed, so the value is already correct. The deleted 'end_time = sched_base_time(admin)' assignment was also harmful independently: it would overwrite the new first entry's pre-calculated end_time with just base_time. Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule") Reported-by: Junxi Qian Signed-off-by: Vinicius Costa Gomes Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_taprio.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 1620f0fd78ce7..366eb7627b30d 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -971,11 +971,12 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer) } if (should_change_schedules(admin, oper, end_time)) { - /* Set things so the next time this runs, the new - * schedule runs. - */ - end_time = sched_base_time(admin); switch_schedules(q, &admin, &oper); + /* After changing schedules, the next entry is the first one + * in the new schedule, with a pre-calculated end_time. + */ + next = list_first_entry(&oper->entries, struct sched_entry, list); + end_time = next->end_time; } next->end_time = end_time; -- 2.53.0