From nobody Sat Oct 4 21:03:17 2025 Received: from szxga06-in.huawei.com (szxga06-in.huawei.com [45.249.212.32]) (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 6C8EA2C0F8F; Wed, 13 Aug 2025 02:10:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.32 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755051027; cv=none; b=ty9rF46a/t9fGGCywk91/PqEHsCJ83OwkzNBpw8VKb2dRVze4Mh19/9tla0voMatwuyvHANqgEKByYeL4lXTFR5QP80DLpkb3jez1ZlcKE+H4PX7NfQwM8PN9+KXjnKaZfgE7Yp5DOCbUTNROb+O9gV+TfHJY/dLy/3/yVp1NrU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755051027; c=relaxed/simple; bh=7WjMSmmNdSXLJ+sm0t2tUevFfljwbQvs+2NXPBJA17E=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=oBAcaaqXZkzBVkYa1C7UYn8CXyQKGAgW79ocwFzfnL7U1D+L07oz4yRKyZO8JLlCxx2gvJ39m3vTipO2lwJ/6u2CtNFCvy8h+Bk0efWCanISlBi+lhexfiVeXQzAlqIT8TDgODtfGZwC2iW90ZXDR2PkYV8U4Un9K1Yt7DlqvGY= 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=45.249.212.32 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 [172.19.163.44]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4c1sLH6Kfbz3Vpwc; Wed, 13 Aug 2025 10:11:19 +0800 (CST) Received: from dggpemf500016.china.huawei.com (unknown [7.185.36.197]) by mail.maildlp.com (Postfix) with ESMTPS id DBCCD140109; Wed, 13 Aug 2025 10:10:15 +0800 (CST) Received: from huawei.com (10.175.104.170) 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, 13 Aug 2025 10:10:14 +0800 From: Wang Liang To: , , , , , , CC: , , , , , Subject: [PATCH net v3] net: bridge: fix soft lockup in br_multicast_query_expired() Date: Wed, 13 Aug 2025 10:10:54 +0800 Message-ID: <20250813021054.1643649-1-wangliang74@huawei.com> X-Mailer: git-send-email 2.33.0 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: kwepems200002.china.huawei.com (7.221.188.68) 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 The multicast_startup_query_interval can also cause this issue. Similar to the commit 99b40610956a ("net: bridge: mcast: add and enforce query interval minimum"), add check for the query interval maximum to fix this issue. Link: https://lore.kernel.org/netdev/20250806094941.1285944-1-wangliang74@h= uawei.com/ Link: https://lore.kernel.org/netdev/20250812091818.542238-1-wangliang74@hu= awei.com/ Fixes: d902eee43f19 ("bridge: Add multicast count/interval sysfs entries") Suggested-by: Nikolay Aleksandrov Signed-off-by: Wang Liang Acked-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel --- net/bridge/br_multicast.c | 16 ++++++++++++++++ net/bridge/br_private.h | 2 ++ 2 files changed, 18 insertions(+) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 1377f31b719c..8ce145938b02 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -4818,6 +4818,14 @@ void br_multicast_set_query_intvl(struct net_bridge_= mcast *brmctx, intvl_jiffies =3D BR_MULTICAST_QUERY_INTVL_MIN; } =20 + if (intvl_jiffies > BR_MULTICAST_QUERY_INTVL_MAX) { + br_info(brmctx->br, + "trying to set multicast query interval above maximum, setting to %lu (= %ums)\n", + jiffies_to_clock_t(BR_MULTICAST_QUERY_INTVL_MAX), + jiffies_to_msecs(BR_MULTICAST_QUERY_INTVL_MAX)); + intvl_jiffies =3D BR_MULTICAST_QUERY_INTVL_MAX; + } + brmctx->multicast_query_interval =3D intvl_jiffies; } =20 @@ -4834,6 +4842,14 @@ void br_multicast_set_startup_query_intvl(struct net= _bridge_mcast *brmctx, intvl_jiffies =3D BR_MULTICAST_STARTUP_QUERY_INTVL_MIN; } =20 + if (intvl_jiffies > BR_MULTICAST_STARTUP_QUERY_INTVL_MAX) { + br_info(brmctx->br, + "trying to set multicast startup query interval above maximum, setting = to %lu (%ums)\n", + jiffies_to_clock_t(BR_MULTICAST_STARTUP_QUERY_INTVL_MAX), + jiffies_to_msecs(BR_MULTICAST_STARTUP_QUERY_INTVL_MAX)); + intvl_jiffies =3D BR_MULTICAST_STARTUP_QUERY_INTVL_MAX; + } + brmctx->multicast_startup_query_interval =3D intvl_jiffies; } =20 diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index b159aae594c0..8de0904b9627 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -31,6 +31,8 @@ #define BR_MULTICAST_DEFAULT_HASH_MAX 4096 #define BR_MULTICAST_QUERY_INTVL_MIN msecs_to_jiffies(1000) #define BR_MULTICAST_STARTUP_QUERY_INTVL_MIN BR_MULTICAST_QUERY_INTVL_MIN +#define BR_MULTICAST_QUERY_INTVL_MAX msecs_to_jiffies(86400000) /* 24 hour= s */ +#define BR_MULTICAST_STARTUP_QUERY_INTVL_MAX BR_MULTICAST_QUERY_INTVL_MAX =20 #define BR_HWDOM_MAX BITS_PER_LONG =20 --=20 2.33.0