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 B3BD43FC5BE; Wed, 20 May 2026 18:42:39 +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=1779302560; cv=none; b=FiifppDfmMLzTgBIDcZWb66miU6QxDW7RItFcAtUbqEdGsN7os7Q8usNpe2Ogkb7tuv9h+TyHVVUccSbUL8hPiyfvxELQdo3/P4H/icKBhUCJR1DPDrrYgJGZY4dfzTz1prvc6zz/Vwo3aCmxfKhhOpf7d7WkQsQb1/Z8XJQI5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779302560; c=relaxed/simple; bh=3UqiF+gvtv97WaQUSKIjraXslN70XUXBEtrx8P6vtAM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LGjV/AaOzpq8RP5JPBS2XDdVWJ+0X4U7qLKhHXbwjQK+PmTczbsi5e52XGNcj/tmukuY+pTVRfqOSnUZ4T4gthAGAfVoazHloO5pg2ImFI5PQp3pY7kYUPQqouaMoKomRYaUXSjabtcm8rtLMu9igqUMyISzpeknVZ+TI/d7qJc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FAOF2J2I; 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="FAOF2J2I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8A381F000E9; Wed, 20 May 2026 18:42:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779302559; bh=AO/grFLjKmW8rz/nCuxAlDqSRdE/Cg39UuG/cdHXM3U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FAOF2J2IN1PAjtyEzUDCbJJb8N2n/6hj0ksvCtRZmVeGXgYlPdtZ8hNQ2HY17fvvI nDwGKrE4vo9rD5Px57dOatj9Io5v9yOYhPsXBC9tCblWFb79zIfPkVsu4n3seIRGmW YRPfNSjbrQWjWsWJKJNpC1Y9A13J5TwfZSo1HRCI= 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 6.6 314/508] net/sched: taprio: fix use-after-free in advance_sched() on schedule switch Date: Wed, 20 May 2026 18:22:17 +0200 Message-ID: <20260520162105.441444850@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162058.573354582@linuxfoundation.org> References: <20260520162058.573354582@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 6.6-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 a01d17d03bf57..6df93d5c2e9d9 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -982,11 +982,12 @@ 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