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emacs 30.2 From: Petr Machata To: Jakub Kicinski CC: Petr Machata , , , , , , , , Subject: Re: [PATCH net-next 2/2] selftests: net: py: ensure defer() is only used within a test case Date: Fri, 9 Jan 2026 16:43:16 +0100 In-Reply-To: <20260109063938.3445c940@kernel.org> Message-ID: <87344e6b7z.fsf@nvidia.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-ClientProxiedBy: rnnvmail202.nvidia.com (10.129.68.7) To rnnvmail201.nvidia.com (10.129.68.8) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SA2PEPF000015CA:EE_|DS0PR12MB8247:EE_ X-MS-Office365-Filtering-Correlation-Id: 15897bb8-9fbd-4e2e-81ad-08de4f964016 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|376014|36860700013|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?Mm5LW3tRM/RA3HomNVnXBymyOBIZFhG8KQn6MvNzVhcuJ/YekhmKIT0at/91?= =?us-ascii?Q?cjmOBHDDB98dEGCVBUKOPXeevrdvHp/BU/NLWR0q7qFBcL29qBG2Q6mn/8WR?= =?us-ascii?Q?UqFI6amCjJBg7R0Z3b5FzpN5UXYKlS0BnFgdR6+Z2prpURq1sldH3XkBLoxj?= =?us-ascii?Q?sAPm/4bRN06yO3jedVdL0/2DV45y7sQiun+VXuSNri1hHJ75sNkIMgLnodQl?= =?us-ascii?Q?Zj1mcMpXnZJvup33znx1Dg6ztGyvSSsLpoxZU1AoW9xY74Xn8N66LQ6BKD+i?= =?us-ascii?Q?fYLPtZkf2SxSBlmL907f1xo6iNkc0i+xc3Zd4hnNuhGoMiL5+8GI6Rt9xWd4?= =?us-ascii?Q?FzWIizh2gWPIojJdym9vltW3yUMQ+40c99A3bkyO9Cl+sH9c7Bnz8eSrRHHl?= =?us-ascii?Q?MudnD0EwiKlBbsD7cmEF3UDeZaePexgrhM99Fq1GDn7KXkXvtfEnv/sHc5kV?= =?us-ascii?Q?5Zi8w71bz5kMUg3Ii6I78BVCtH8+4zZ2AK/YpHvW8MWM3hvSXh3HS3C9eeK/?= =?us-ascii?Q?rNDCBdRpFT080xBKVV8GM3POpjxxO7d3rZ0kBiKzQXQeKLaEQVyMrjB0Pn1K?= =?us-ascii?Q?1VTeerpYFy8zyQeOpcHNM8i8UfUecuyHx3SI5f5novcNUTTGmHPNQOujcwAZ?= =?us-ascii?Q?2qnJr8tpXKNANtHEVFzZozORh9+AJSulgiOkVoOw2WyV4ah7ZN0F2l5T4pk9?= =?us-ascii?Q?eG+j6aZnvPzLiwMRTYNxGtJHZStpLrsvKYY/OeSXhMfnVCnRJfm5II4R1LgK?= =?us-ascii?Q?TDl9tLs60g35InQ+zGsvEOLTZGyEkVDMSjFAvUVReylXjNvTcF0ZGVOntpxF?= =?us-ascii?Q?CpEos1823ic+zyzGbjDz6GTfPoaK7rBcSg0TsGNs4D/XFtymG7ImVIeYsALG?= =?us-ascii?Q?RtNRbRks7iyBgUmaREPBoyeO7sodA8IV0+VwLXmqgTwo21zRTlYc34cWBcZB?= =?us-ascii?Q?X1iZDKHafAQTktFFqg4x3h9AL7KiUUnmIUJAWq/9wx+RI2TU3ndTyUMWakgB?= =?us-ascii?Q?H6guW8Grry4Uk2tojgFsGMosQO0ALUTQ//iVd54TRmgXB5NNpWsn6bEew4yT?= =?us-ascii?Q?zFHUi0k1ZhamfICUjWu3AeYvnHJVCZjO7mI7sbBMEWd4hLWICvIUeFCWZX0a?= =?us-ascii?Q?fIrL7udw5Qr6SrHeNjKaYV6YdaFnr0PxZ46WQaD/ujgvSksUSJmYqVu3sr2/?= =?us-ascii?Q?TKehG6ohjBsaJ+49Riw9etItU/sHraph7QvjVXBpvof8kr8d27yB9xbeZZQt?= =?us-ascii?Q?mgBf3ZOHfOf/rXeiVs+xblN2rMRaSzU6Itg5rheSFFAWOwpF7e/DMtOd+H+0?= =?us-ascii?Q?ldbgYF7ioH81veu5yr+3lbz9deeslRzCCm1aLMNJvFWn14tRD/vUGWFPTt6G?= =?us-ascii?Q?zxSOi7EcmeAT72+B39IcYcORG10pC2HCtUNKwbj2iBGg+8bMUXz9KG1rJWVF?= =?us-ascii?Q?aKnYTaQrT9duk7IOxt+bKltcGu+5W6J+W0kvDYUIOj9+vx8LbjYYcHahggbF?= =?us-ascii?Q?A3/9o9aMbw20/b+MI/lE1zrhT6YATevUQZ9KcNyIQ2OUIPUhoCuAsJziTMCe?= =?us-ascii?Q?stRtdUv9J80zq16TX+c=3D?= X-Forefront-Antispam-Report: CIP:216.228.117.161;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge2.nvidia.com;CAT:NONE;SFS:(13230040)(82310400026)(376014)(36860700013)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Jan 2026 15:46:27.0616 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 15897bb8-9fbd-4e2e-81ad-08de4f964016 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: SA2PEPF000015CA.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB8247 Jakub Kicinski writes: > On Fri, 9 Jan 2026 09:23:54 +0100 Petr Machata wrote: >> > I wasted a couple of hours recently after accidentally adding >> > a defer() from within a function which itself was called as >> > part of defer(). This leads to an infinite loop of defer(). >> > Make sure this cannot happen and raise a helpful exception. >> > >> > I understand that the pair of _ksft_defer_arm() calls may >> > not be the most Pythonic way to implement this, but it's >> > easy enough to understand. >> > >> > Signed-off-by: Jakub Kicinski >> >> I think we achieve the same without the extra globals though? Just drain >> the queue and walk through a copy of it? >> >> defer_queue = utils.GLOBAL_DEFER_QUEUE >> utils.GLOBAL_DEFER_QUEUE = [] >> for i, entry in enumerate(defer_queue): >> ... >> if utils.GLOBAL_DEFER_QUEUE: >> warning / exception > > That's what I had initially (IIUC), I was assigning None to the queue, > and then [] only while inside a test case. It gets slightly hairy > because either we need to pass in the queue into the flush function; > or we have to restore the queue if something raises and exception during > flush (in which case ksft_run() prints a warning and calls > ksft_flush_defer() one more time). Hmm, yeah, the exception robustness will complicate it. OK, let's have it your way then :) Reviewed-by: Petr Machata