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 99CEE369D67; Wed, 20 May 2026 17:44:45 +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=1779299086; cv=none; b=KE326BiYKQ6Jv3ZZBoXX1Gqz5L+7MRiRdlj4q9p3fGeL3ncPmvQoWPvfdi9K1YFUFcC//oSjgMMoxTYUAoMjX6tO/QrtFTT7fEcNqTvQhuPhr/MeIKUbQxacQtU861lC4AE4AUfH8/K9iipE60WSyRXKB7UU8zfX0K3hWcmnIIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779299086; c=relaxed/simple; bh=2esuF5Ehx7XD8w64SlUEjhlTAtQ2CLwt9SA1Pv0dLq8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hdGasusl07JSM5G3duMvmLHf9ZWTm7/yqeRDhBAayd7JiS8WKb454wpreFLj32J7NMVTkiUNGIqE6lW2C4WSL82GwpP11TkDw82MCohdcbRbvHp6++ASDw3gSpmSJxvtoAx/6dj79GJldm/FS2J63nYRoBg/Ba6exsFstYdXMlQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bca6WkwL; 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="bca6WkwL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01A301F000E9; Wed, 20 May 2026 17:44:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779299085; bh=VJHFlvBQUoKsRDQ7PQqksov//dvyTdQjZ7gMpWKbBwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bca6WkwLvUZWjQJIWtNq3sDBxFvZ7GwE44TmW5uiZRLcUX27dna0fp+1aTJ5RF3Us cond1/VXNrANFDTUvPvu9PSapzsaa+WGGItLl6eCBfxr7sgnUVHeAFFhMxV7Jk7pz/ j6EIwd4xB1+7Wf3cHX7QUmAvC83aDAGTjkH3HS70= 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 6.18 620/957] net/sched: taprio: fix use-after-free in advance_sched() on schedule switch Date: Wed, 20 May 2026 18:18:23 +0200 Message-ID: <20260520162147.978156321@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162134.554764788@linuxfoundation.org> References: <20260520162134.554764788@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 6.18-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 39b735386996e..91b85360f8091 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