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 51DF9340293; Sat, 30 May 2026 17:20:48 +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=1780161649; cv=none; b=pADAw09TYAVY3WDk7SZlFDa9LCLgljZNhJXCUeLaLTRVRdfe5buz5MHVo1X23y62duP7Ues0nWVlmfTN9CdHAJFk7C572h1wBIeBxI1PDkuQeUpQjv7diMG/+LWWK4qByqpLhNmikpNhnTi1uPJl2QxSD1pSMD2RxXtGq+oH2Lk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780161649; c=relaxed/simple; bh=6RjE1c2fYY8ewrMgxh/r63o/1z58OIpnwOAYIWXMU/s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YFsk/Rses4tz6kiDu3QPmMubviSSpwYJ2/M5rIDH3cvdym2lxdkEeGQ8vLa0B9eXLn0CFwYfWpSQKKCeg+0vfQEVZudq8vmTbz3GpPVaCYAO8/+S9Znujx+FH9KBHlKTTA3lT8fv3YkePiTWsYAXLofVQjgHlAFhnQyDg3S3r00= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=b0pVlxuh; 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="b0pVlxuh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9487E1F00893; Sat, 30 May 2026 17:20:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780161648; bh=ikGAWtpVvkVCx4k8BeokdLfQVF3j5chhMkSP0Jv2PUs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=b0pVlxuhzwbnalFGZdtzAgpjgLA75VWGAXJeQ4NBZxh9MaJHJfH3lCs0oSm+ijDNK fRMIKh8109wwNvp885EF/h6oERJBiuHG8Beeimx2/NuwrM18SiKcQ6Z8U1crYlVo6V U6O3ioIzxGnehHQgcjWA9MzdssiY4De3GnM1YwD4= 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 6.1 685/969] net/sched: taprio: fix use-after-free in advance_sched() on schedule switch Date: Sat, 30 May 2026 18:03:29 +0200 Message-ID: <20260530160319.422949820@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160300.485627683@linuxfoundation.org> References: <20260530160300.485627683@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 6.1-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 ce529b9448819..8da723f054f56 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -739,11 +739,12 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer) end_time = min_t(ktime_t, end_time, oper->cycle_end_time); 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