From nobody Sun Oct 5 09:07:15 2025 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (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 CD1BD220F3E; Wed, 6 Aug 2025 09:28:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754472539; cv=none; b=knpODpBm1h+IU+3zbsush/5RoOE2CgMJ2XSz3JH/KznjgggWHnyUdDsW8VGYMj/f4YpVPaeP+nqDk0sC0tHKSyddQiYP7tRZTGI/5RJiRBJ0c6aNoTImd2l2yNvxK9aXUeT1GwLFVxus/LSFl89qPBDVFiW7rVhYYuUV6Dh/arA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754472539; c=relaxed/simple; bh=bhJ5WP3HwvnnIMpMD69DY2iqOt3OMJucp0B8rJ3Cx/w=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=KPfoDiBHcY39ch2bMycZ6Waqz06dil6MflqxnhV9s3YWOP8ki/ZbAzAeGCXZkHCy1aZ6Zlm4IlEHsL1kg6xfHVYTJSt8jIr0VtTsPYEzG7gszcEkCCnAZPtHI3qRhVCYD1amGJJ+SZFROGEyih4mgVhT3Pma60ncqf2mZjUfzxs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.194]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4bxlM55DfVztScj; Wed, 6 Aug 2025 17:27:45 +0800 (CST) Received: from dggpemf500016.china.huawei.com (unknown [7.185.36.197]) by mail.maildlp.com (Postfix) with ESMTPS id 362C7140156; Wed, 6 Aug 2025 17:28:47 +0800 (CST) Received: from huawei.com (10.175.124.27) by dggpemf500016.china.huawei.com (7.185.36.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 6 Aug 2025 17:28:46 +0800 From: Wang Liang To: , , , , , , CC: , , , , , Subject: [PATCH net] net: bridge: fix soft lockup in br_multicast_query_expired() Date: Wed, 6 Aug 2025 17:49:41 +0800 Message-ID: <20250806094941.1285944-1-wangliang74@huawei.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To dggpemf500016.china.huawei.com (7.185.36.197) Content-Type: text/plain; charset="utf-8" When set multicast_query_interval to a large value, the local variable 'time' in br_multicast_send_query() may overflow. If the time is smaller than jiffies, the timer will expire immediately, and then call mod_timer() again, which creates a loop and may trigger the following soft lockup issue: watchdog: BUG: soft lockup - CPU#1 stuck for 221s! [rb_consumer:66] CPU: 1 UID: 0 PID: 66 Comm: rb_consumer Not tainted 6.16.0+ #259 PREEMPT(= none) Call Trace: __netdev_alloc_skb+0x2e/0x3a0 br_ip6_multicast_alloc_query+0x212/0x1b70 __br_multicast_send_query+0x376/0xac0 br_multicast_send_query+0x299/0x510 br_multicast_query_expired.constprop.0+0x16d/0x1b0 call_timer_fn+0x3b/0x2a0 __run_timers+0x619/0x950 run_timer_softirq+0x11c/0x220 handle_softirqs+0x18e/0x560 __irq_exit_rcu+0x158/0x1a0 sysvec_apic_timer_interrupt+0x76/0x90 This issue can be reproduced with: ip link add br0 type bridge echo 1 > /sys/class/net/br0/bridge/multicast_querier echo 0xffffffffffffffff > /sys/class/net/br0/bridge/multicast_query_interval ip link set dev br0 up Fix this by comparing expire time with jiffies, to avoid the timer loop. Fixes: 7e4df51eb35d ("bridge: netlink: add support for igmp's intervals") Signed-off-by: Wang Liang --- net/bridge/br_multicast.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 1377f31b719c..631ae3b4c45d 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1892,7 +1892,8 @@ static void br_multicast_send_query(struct net_bridge= _mcast *brmctx, time +=3D own_query->startup_sent < brmctx->multicast_startup_query_count= ? brmctx->multicast_startup_query_interval : brmctx->multicast_query_interval; - mod_timer(&own_query->timer, time); + if (time_is_after_jiffies(time)) + mod_timer(&own_query->timer, time); } =20 static void --=20 2.34.1