From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 EFE3C34A309; Tue, 26 Aug 2025 13:13:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756213989; cv=none; b=e0YIpNMG0oPyU4Ew5AxUKURMm/DKVFb4/zxuXCkRTMIOqv+syQNHTqaTMIDXvc8+hKbg18ho1UBGKQaMz+EQfcTcH2W60G96BsHlcj0L/3sgrNJuK6gbzgG59MLLQqnxV9k6zgl4ZYFGWoPaGPorTZOH5VL2g+fdjV4nPaPdUVs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756213989; c=relaxed/simple; bh=qXCT162YGz/iYUt7KztYuxaLpw7Z4vjG+X8WX0X4eN0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Mt0PKCEfkR3tVx4JjgzWLjra6rtaANzQjkoyzc263SfxMlI+KuJMAisB+ajs465MrqYF01ErHTDEkCxuZq5GgX5ob0jLz/sVZu9ArWvpMdA8EDiY2A2brDhsZf6LuUYppYFL9P1EqXwVm9CJE3eWSGO2rRU9v065oeuzQ+Tf/LU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MRFdpqDm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="MRFdpqDm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D2C1C4CEF1; Tue, 26 Aug 2025 13:13:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756213988; bh=qXCT162YGz/iYUt7KztYuxaLpw7Z4vjG+X8WX0X4eN0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MRFdpqDm0hCSft3ZwUCmKwD/AIaYPpXeVLIdo+SEXcuVxP+LJOquNfbCN5NP4IoAE njGM+hJnyGx3LwgRIhce5xrHWVYPtGHiiZWW194ZdhAHMgpcZ+7kYKf1PbxIion0k0 PVz9DY9A8WI2y5rrniYcsK1n6glWzOTHyU6kv5Ag= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nikolay Aleksandrov , Wang Liang , Ido Schimmel , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 556/587] net: bridge: fix soft lockup in br_multicast_query_expired() Date: Tue, 26 Aug 2025 13:11:45 +0200 Message-ID: <20250826111007.168049074@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110952.942403671@linuxfoundation.org> References: <20250826110952.942403671@linuxfoundation.org> User-Agent: quilt/0.68 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wang Liang [ Upstream commit d1547bf460baec718b3398365f8de33d25c5f36f ] 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@huawei.com/ Link: https://lore.kernel.org/netdev/20250812091818.542238-1-wangliang74@huawei.com/ Fixes: d902eee43f19 ("bridge: Add multicast count/interval sysfs entries") Suggested-by: Nikolay Aleksandrov Signed-off-by: Wang Liang Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250813021054.1643649-1-wangliang74@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- 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 fa16ee88ec39..f42805d9b38f 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -4807,6 +4807,14 @@ void br_multicast_set_query_intvl(struct net_bridge_mcast *brmctx, intvl_jiffies = BR_MULTICAST_QUERY_INTVL_MIN; } + 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 = BR_MULTICAST_QUERY_INTVL_MAX; + } + brmctx->multicast_query_interval = intvl_jiffies; } @@ -4823,6 +4831,14 @@ void br_multicast_set_startup_query_intvl(struct net_bridge_mcast *brmctx, intvl_jiffies = BR_MULTICAST_STARTUP_QUERY_INTVL_MIN; } + 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 = BR_MULTICAST_STARTUP_QUERY_INTVL_MAX; + } + brmctx->multicast_startup_query_interval = intvl_jiffies; } diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 067d47b8eb8f..ef98ec4c3f51 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 hours */ +#define BR_MULTICAST_STARTUP_QUERY_INTVL_MAX BR_MULTICAST_QUERY_INTVL_MAX #define BR_HWDOM_MAX BITS_PER_LONG -- 2.50.1