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b=cORzHGK0FTZtIpLS2SwHciD2VSvE+bnXGHFXCP5f5+QT/F2Z/DM5kK1Oc5n/vN7ABhYC3orTS1nqkel2uJFwwqGCNCYiOMDyl6hM2XtRlyT/zrlRdug8ycQh6Kle/lXXwiyyzWhcLnKZFcwKplE98ZNO1T5/yrOzYsLD5VtSGnHJZD8erH9XXicTwVMrp+3zLve4kqeG8+lH4PlPwCMdCjd1vDc5bY2s69388OrRKOVoY4p3oMEm4jDGX7/InDPWyQAcK27fBRUFQPvbwLnexPgeJH3HtlMWDxyF8S5OMwZC4EQeG/TY4DvZN3n4nrgZn3kqf7uS1bXNSmtFkF9cPA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from SA3PR12MB7901.namprd12.prod.outlook.com (2603:10b6:806:306::12) by DS7PR12MB6069.namprd12.prod.outlook.com (2603:10b6:8:9f::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.71.12; Tue, 26 May 2026 06:49:08 +0000 Received: from SA3PR12MB7901.namprd12.prod.outlook.com ([fe80::6f7f:5844:f0f7:acc2]) by SA3PR12MB7901.namprd12.prod.outlook.com ([fe80::6f7f:5844:f0f7:acc2%6]) with mapi id 15.21.0048.019; Tue, 26 May 2026 06:49:08 +0000 From: Ido Schimmel To: netdev@vger.kernel.org, bridge@lists.linux.dev Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, razor@blackwall.org, horms@kernel.org, sdf@fomichev.me, Ido Schimmel Subject: [PATCH net 1/3] bridge: Fix sleep in atomic context in netlink path Date: Tue, 26 May 2026 09:48:16 +0300 Message-ID: <20260526064818.272516-2-idosch@nvidia.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260526064818.272516-1-idosch@nvidia.com> References: <20260526064818.272516-1-idosch@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: FR4P281CA0147.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:b8::7) To SA3PR12MB7901.namprd12.prod.outlook.com (2603:10b6:806:306::12) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SA3PR12MB7901:EE_|DS7PR12MB6069:EE_ X-MS-Office365-Filtering-Correlation-Id: 2300f2c5-f8ba-4772-e9df-08debaf2e2f5 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016|6133799003|3023799007|11063799006|18002099003|22082099003|56012099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?WUjCCzakX7/248Mi2RK2Tua4nLVjM9B/qiygLHJKquzDGIEi/QwU7pl9HPH/?= =?us-ascii?Q?doF/iY42kouQZugkprBtFZSw42uaVTIVl6QaSNBPyOOr6rJ5oqy7220/JN6y?= =?us-ascii?Q?c0ZEUMLJifNBBuK0kKNNs1MdvODXTGReIznOJqD6fawHsJyYwlXETFUx7Vz0?= =?us-ascii?Q?JUSRDREUS+227VQk6t7e84GZq1yI7sbYk5ieaIgkj8yDG93wg/yeAyOwx/65?= =?us-ascii?Q?3KeEeED8pnvekUF8upJbTa3JRY5DgiLUWZjwXt/qo8CczFPHsi8aWTVRSTJS?= =?us-ascii?Q?9AP7A22+j0eT3TKN6Ohh3vYittRKnvUkbPjkyzj3IC6y3MghTXmFGwtKjUj2?= =?us-ascii?Q?Mc/TGxG21mujnYuyAAydcU/2c+/okuXq+JugzTxyzALz26KeHmoV7gkxks0I?= =?us-ascii?Q?dAwLOO8ptjGgxtrgakD0si8Ttom78KVDfsPe6uM343mE5cKdqez1QQhoYEr7?= =?us-ascii?Q?IGCsxgg+9uP4MvM9W+Db9m2BUUWX+zR+L3vICRzvYFFyMTXSBPY+rgvq8XWM?= =?us-ascii?Q?gVLAtxIIpzTQbh9M5XAx27+74/ccp1fQGA3iaehmaluPJuv2lcboAYJB87cS?= =?us-ascii?Q?dtdua6hJVkj8PnPMKFN9ZmJyyy6wFXqh/2TWihFSO8P5lNts/kWFUysvehLl?= =?us-ascii?Q?IDVyaASyqUSWcNUH+mk/LlgVz1OClX74Q6KRPBOH/9MNgdTmcCv61XwD5hBz?= =?us-ascii?Q?MSx/Q4QU7j0Z8xW2d8x+S9RMkJDoUpVuUDSNxlVxE05wooB/wRPaaPbdo7zJ?= =?us-ascii?Q?QIk/QmOZKCdDv22JZF3lvuyLyTLyMADsjzpK+SSFQdvxWVMA/mk5yIEAX2lZ?= =?us-ascii?Q?oujEl+4b9eBxNtEnTFB8enQMCNFuHP+drAMQfRIi/eERkw7IV5afqGqUBaNA?= =?us-ascii?Q?oV2tXZFCAhImdclY6EKsYFjstKtp7WED6+jzEQpJeFF0cOrOn2kQBtZtndV6?= =?us-ascii?Q?E6oQZp3J0oTLYEfrVx5bhn7OB5A9TJyzQXDx7bzqUjs45t9j8eYC78kjRb+3?= =?us-ascii?Q?U9ahOI+2JV9e5cIfR9ZQdpT07Zaj6Jv69EG1NMtuyod3sz3KFbu0++KNcgik?= =?us-ascii?Q?40MI/c02o7gv3LHHts9ZPto54xdDzG8GIpO3szIeuxsKvC87LdQgyJcLy0Iz?= =?us-ascii?Q?p/GSDh3iJ5Tc7vgiaKamIpPxkyewfAYoYdGa6HIfgjunbQCeSh1rDIxYyGvt?= =?us-ascii?Q?zaxop2nU7GYmEN7q43F68yA4nQMFMDlkwAPlGgXqs/aW4e99qjJYaOjSlnPs?= =?us-ascii?Q?Q59nnSIjIlmjPCPRDlMIvcBEjnICcg2VOfFwBGAUT6Vcc6MpIyA+uUsm4pIA?= =?us-ascii?Q?r14giYR23HqDExh8KhpTisV18EjeETyghJzVFZ0FxyJArpcYklgA5vIsfbFE?= =?us-ascii?Q?BGsJ1b9Ox+l3hGQsjrydKMT+5q5uvRWhM+h4GxxYu+BUbM5zi2GN6ZzKz/9U?= =?us-ascii?Q?ol/oedamnHcW2f2fJWpNL5swxzfVu48uGiV7Etspx+qzhVULXn07jTaTMwBX?= =?us-ascii?Q?Yfj/ZnC8JCGPDPiNQjkveb5n4yZGsTt2QG5Mx2BxP6gIq9ktO8FRPQn1UHjX?= =?us-ascii?Q?HOQ7hw8V542UV3/Ygi2QmkABCAW+xQv1qQbfqnYiuWiY8s+8CgXlyCxhqkLq?= =?us-ascii?Q?91gSIkeEvukOe5sITU0E/P6goDn9bzot820IR32ie6pLiyS3aVlK9WE4+4pK?= =?us-ascii?Q?kzTeQ5T1rfWo2QXO46TvbcyeTFda1huHQlsWrrxmcLu32vtq?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2300f2c5-f8ba-4772-e9df-08debaf2e2f5 X-MS-Exchange-CrossTenant-AuthSource: SA3PR12MB7901.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 May 2026 06:49:08.7561 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: yFF3AjTqWYrm5Nir1zAfEs8LzobNh3XiQTs/3HI0b4Y0qlCQIO5Wy9NgMRGxiEF0hZBC5Z7gdksnXAYgtY4MSQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR12MB6069 Since the introduction of the netlink configuration path for bridge ports in commit 25c71c75ac87 ("bridge: bridge port parameters over netlink"), br_setport() was always called with the bridge lock held around it. Back then this decision made sense: The bridge lock protects the STP state of the bridge and its ports and at that time the function only processed three STP related netlink attributes (cost, priority and state). Nowadays, br_setport() processes a lot more attributes and most of them do not need the bridge lock: * Bridge flags: Only require RTNL. Read locklessly by the data path. Annotations can be added in net-next. * FDB port flushing: Only requires the FDB lock. * Multicast attributes: Only require the multicast lock. * Group forward mask: Only requires RTNL. Read locklessly by the data path. Annotations can be added in net-next. * Backup port and NHID: Only require RTNL. Read locklessly by the data path. This is a problem as the bridge calls dev_set_promiscuity() when certain bridge port flags change and this function can sleep since the commit cited below, resulting in a splat such as [1]. Fix this by reducing the scope of the bridge lock and only take it when processing the three STP related attributes that require it. This is consistent with the multicast attributes where each attribute acquires the multicast lock instead of having one critical section for all relevant attributes. [1] BUG: sleeping function called from invalid context at net/core/dev_addr_lists.c:1262 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 356, name: bridge preempt_count: 201, expected: 0 RCU nest depth: 0, expected: 0 2 locks held by bridge/356: #0: ffffffff919473a0 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg (net/core/rtnetlink.c:80 net/core/rtnetlink.c:7002) #1: ffff888115072d58 (&br->lock){+...}-{3:3}, at: br_setlink (./include/linux/spinlock.h:348 net/bridge/br_netlink.c:1117) Preemption disabled at: 0x0 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) __might_resched.cold (kernel/sched/core.c:9163) netif_rx_mode_run (net/core/dev_addr_lists.c:1262) netif_rx_mode_sync (net/core/dev_addr_lists.c:1428) dev_set_promiscuity (net/core/dev_api.c:289) br_manage_promisc (net/bridge/br_if.c:135 net/bridge/br_if.c:172) br_port_flags_change (net/bridge/br_if.c:242 net/bridge/br_if.c:747) br_setport (net/bridge/br_netlink.c:1000) br_setlink (net/bridge/br_netlink.c:1118) rtnl_bridge_setlink (net/core/rtnetlink.c:5572) rtnetlink_rcv_msg (net/core/rtnetlink.c:7005) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1318 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sock_sendmsg (net/socket.c:787 (discriminator 4) net/socket.c:802 (discriminator 4)) ____sys_sendmsg (net/socket.c:2698) ___sys_sendmsg (net/socket.c:2752) __sys_sendmsg (net/socket.c:2784) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Fixes: 78cd408356fe ("net: add missing instance lock to dev_set_promiscuity") Reviewed-by: Nikolay Aleksandrov Signed-off-by: Ido Schimmel --- net/bridge/br_netlink.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index c04a4d0889ae..b9591dd755f9 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -1000,19 +1000,25 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[], br_port_flags_change(p, changed_mask); if (tb[IFLA_BRPORT_COST]) { + spin_lock_bh(&p->br->lock); err = br_stp_set_path_cost(p, nla_get_u32(tb[IFLA_BRPORT_COST])); + spin_unlock_bh(&p->br->lock); if (err) return err; } if (tb[IFLA_BRPORT_PRIORITY]) { + spin_lock_bh(&p->br->lock); err = br_stp_set_port_priority(p, nla_get_u16(tb[IFLA_BRPORT_PRIORITY])); + spin_unlock_bh(&p->br->lock); if (err) return err; } if (tb[IFLA_BRPORT_STATE]) { + spin_lock_bh(&p->br->lock); err = br_set_port_state(p, nla_get_u8(tb[IFLA_BRPORT_STATE])); + spin_unlock_bh(&p->br->lock); if (err) return err; } @@ -1114,9 +1120,7 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh, u16 flags, if (err) return err; - spin_lock_bh(&p->br->lock); err = br_setport(p, tb, extack); - spin_unlock_bh(&p->br->lock); } else { /* Binary compatibility with old RSTP */ if (nla_len(protinfo) < sizeof(u8)) @@ -1203,17 +1207,10 @@ static int br_port_slave_changelink(struct net_device *brdev, struct nlattr *data[], struct netlink_ext_ack *extack) { - struct net_bridge *br = netdev_priv(brdev); - int ret; - if (!data) return 0; - spin_lock_bh(&br->lock); - ret = br_setport(br_port_get_rtnl(dev), data, extack); - spin_unlock_bh(&br->lock); - - return ret; + return br_setport(br_port_get_rtnl(dev), data, extack); } static int br_port_fill_slave_info(struct sk_buff *skb, -- 2.54.0