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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Petr Machata , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, AutonomousCodeSecurity@microsoft.com, tgopinath@linux.microsoft.com, kys@microsoft.com Subject: Re: [PATCH net] nexthop: initialize extack in nh_res_bucket_migrate() Message-ID: <20260714104428.GA838500@shredder> References: <20260713221551.3344650-1-xmei5@asu.edu> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260713221551.3344650-1-xmei5@asu.edu> X-ClientProxiedBy: FR4P281CA0185.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:ca::18) 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_|BL3PR12MB6619:EE_ X-MS-Office365-Filtering-Correlation-Id: 5311f34c-7800-44b5-f7be-08dee194e87e X-LD-Processed: 43083d15-7273-40c1-b7db-39efd9ccc17a,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|23010399003|1800799024|56012099006|11063799006|18002099003|22082099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?S0Y1snOctTkZr2RkjoR5OabW8pp8LEjXe2Tod33m356l9aZN2RRTS7q8DQAE?= =?us-ascii?Q?+tOavbh3H2PIw+ln1nZtjSiyjSjV5kcgIVXhZd0L6zR78f19YFbhECXcYDTB?= =?us-ascii?Q?jMJp7MfzZ8r0mvyXslhwRAtWh2EwJ2rFY7FrwkRlzmLqHibPIgPEvZUflkmc?= =?us-ascii?Q?3VOUNslX239lYpWKBUugpD7xtCcfkexSvT7gD5DGjioLUlAgKC4Q6JUI/8oW?= =?us-ascii?Q?iDzFda8PSNE59l6ncVG70bedRRcOP3cT5KVGFo8YwVHsz7wET4iBbcfxGzUK?= =?us-ascii?Q?368+wYfsiIoLJFPeABz3605gUPU/UOl2auGTYihapT39D2nus96OsSCDOh3l?= =?us-ascii?Q?42z/JtSCeP4T1mLKdP759og56wfDatmg7w8GmsVPeuL3gtphbNX2Zsyp2rl5?= =?us-ascii?Q?PBlqdVhnwSNZn8CsJOcxowOmnsvvt5unthBU7vZrlB6Hsbn/+Ho4zoqDLFIh?= =?us-ascii?Q?LZQ4fjUAgNwDCjl9U+Se28koeUdKHO+qWfYmyBIviaNsCy12MxI615GoXfP+?= =?us-ascii?Q?uwi92QFHB0lik0lPWLOkiHFm7Jd0a9PgyWQGEOA7h0q9e1nPXeLMg3618AkH?= =?us-ascii?Q?bmO/HV2EOl3ZK7+qBxrYV5Y08AL7S/z9UY0WORd1QEoLL0tj+WGQzpt965s+?= =?us-ascii?Q?0G/YXdl91+Qp/IQBabgwOIK/TNsWabuW9uFejdbPGPyDLuetd3iEwTwfSm14?= =?us-ascii?Q?2meBIsy1WDGaAZfsX3IHaJDKruMrvdGXlVkwuhY0bbOJBuw+SD3VRCUaE5s7?= =?us-ascii?Q?JH7eWwPlAzUiejr05rXR4RQWT+6gcZMlkQRX4h3kFWDggAM9Y9XsQzGpTnta?= =?us-ascii?Q?Umeuq8vHajvv4h0YyHnc6Aee7fwz4nu/CRFyzw3rYToLMSS0qoDK9wx6X38V?= =?us-ascii?Q?bMUWE6V1oG/+uls3W4hAUwKJxhf6X6477jwcieMlLgQWOnI1gzSC7wWsM5GF?= =?us-ascii?Q?aQEOyEu4KZ4a9MlglhlxgvCfourGbf4vjVFIJFKhF5jxv3AfF509McTqwRFv?= =?us-ascii?Q?WG0+gf8anBBMLVfq0RmYTaLmwx+4BUpp2LdhYLPQ0nydiJyiLJgJFU5Qu+CJ?= =?us-ascii?Q?A9JXHslC2T7CDH0SwTrgWdQu021Chxzda+R/heKbi5TbrOsZBL5JEEIU4N4k?= =?us-ascii?Q?BEPeQ2DOL2pXLrI/0v7ruSw2DV5VyC+s+odPeAF6nI0wZObnP1GMQzlYsu1F?= =?us-ascii?Q?h+Khg7KOI91904tEvL/bosXY/jQtapX/RIpZ3YBPffW2njlCtA2TSDbM7EXK?= =?us-ascii?Q?Wn5lmUJ0TEVRb257jpKklSWNef6JZa2ptiRW0szdtThJouxLrl0yK10s8ubU?= =?us-ascii?Q?p59maztw171NnE8ThXBV5ZvLneWOECil3fDcnG8AagsSSx/suomHaK5Al0k9?= =?us-ascii?Q?Up7yKLirFeQJJ89cW1t7BrIvSWNzD7+MA597ZbA7foDrwH0yjeMUoypIpAjO?= =?us-ascii?Q?DLeH+tBtjvB7kbTTqOuBs64lJwG2pBkhPRQYFLMei19CFvLiwS7ULK6s2kDg?= =?us-ascii?Q?HhA2ltuXHah5azuC5mPNtab4i8+a9zi4PZaDheEdd6R7QSj6/DnbaocEizYD?= =?us-ascii?Q?5UGjbaopiPIPmj2enxXG+jscmAckn6fS1pthYQNHMfJFSDQkJb73cum2aTxn?= =?us-ascii?Q?bq1BJYZBy3q9Lg1T7jx09WAI8rWTxZVbT2q61siOnCwRdg1Y4heYrX5hO9j/?= =?us-ascii?Q?zGH/uOWz0TJh3Yttloc/eN0WvWMlRlCHjS/cBPTvRrTOBqeoOnKxYvV1r/Fr?= =?us-ascii?Q?EXY0hqrjpQ=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5311f34c-7800-44b5-f7be-08dee194e87e X-MS-Exchange-CrossTenant-AuthSource: SA3PR12MB7901.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Jul 2026 10:44:40.8139 (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: P44j/2OF+Qdj5CaL8DYkDif0wrfV0NX3HTCliPMP4y5W/yxjpArybhaeVDiXBBbGKmT6p+FqGrdQrlWkjGUGqQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL3PR12MB6619 On Mon, Jul 13, 2026 at 10:15:51PM +0000, Xiang Mei (Microsoft) wrote: > nh_res_bucket_migrate() passes an uninitialized netlink_ext_ack to > call_nexthop_res_bucket_notifiers(). When > nh_notifier_res_bucket_info_init() fails (e.g. the kzalloc returns > -ENOMEM), the error is propagated back before any notifier sets > extack._msg, and the error path formats the stale pointer with > pr_err_ratelimited("%s\n", extack._msg). With CONFIG_INIT_STACK_NONE > this dereferences uninitialized stack memory: > > Oops: general protection fault, probably for non-canonical address ... > KASAN: maybe wild-memory-access in range [...] > RIP: 0010:string (lib/vsprintf.c:730) > vsnprintf (lib/vsprintf.c:2945) > _printk (kernel/printk/printk.c:2504) > nh_res_bucket_migrate (net/ipv4/nexthop.c:1816) > nh_res_table_upkeep (net/ipv4/nexthop.c:1866) > rtm_new_nexthop (net/ipv4/nexthop.c:3323) > rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) > netlink_sendmsg (net/netlink/af_netlink.c:1900) > Kernel panic - not syncing: Fatal exception > > Zero-initialize extack so _msg is NULL on error paths that never set it. > > Fixes: 7c37c7e00411 ("nexthop: Implement notifiers for resilient nexthop groups") > Reported-by: AutonomousCodeSecurity@microsoft.com > Signed-off-by: Xiang Mei (Microsoft) Reviewed-by: Ido Schimmel It's very unlikely that nh_notifier_res_bucket_info_init() will fail. I assume that fault injection was used. remove_nh_grp_entry() also doesn't initialize extack, but call_nexthop_notifiers() is using NL_SET_ERR_MSG(). Still, the same problem can happen if a listener is returning an error without setting extack. Please send a separate patch (targeted at net-next, no Fixes tag) to make remove_nh_grp_entry() consistent with nh_res_bucket_migrate().