From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CY3PR05CU001.outbound.protection.outlook.com (mail-westcentralusazon11013026.outbound.protection.outlook.com [40.93.201.26]) (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 0B2803B19DE for ; Fri, 10 Apr 2026 08:58:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.201.26 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775811543; cv=fail; b=tmtkErEiH7LtVY8w8Tdk9p3brnfGWqTOaJZjLatx8yBeS9kyMbnkQyPeyPgjVsqOdLNJ2zyxDY+zEhkakgih+qXyZ0VJ6hZHsZnNdK4ihiMktzDokwBrngbSSIRHgyi3OqK32u8X9i5ImxYEAJz0Y0SWArWD48n2QuTG1bRu0pc= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775811543; c=relaxed/simple; bh=X+uJWQzOpK1J2jwmlbRv9GvSBIzDsDyNTpEkWnX/J0g=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=C1xFAErhF9Ad6caKhHZ8VBybaEJcDyop83KhXLm54mtft+GRq+Yg7zc3MhKn7+sqHdaAzxDNqXql+si98jTrao/eMrSoFG2OJIZn9p9YiFqDL4rV+777p64+bldmL86/ETkj/aWgq0/ZUnyEqN5KFROCaG+WSx7JsvdddbGS+Is= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=Vi/v6jlh; arc=fail smtp.client-ip=40.93.201.26 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="Vi/v6jlh" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=tPnU8RnGhjU0Avc195Xi74RIGiiVyUMiVbxID7Fm/5dxQfsXgm+O9w9444F/YD+lZKWMsUTzorVN5iI5wTr73teGz9CcUNjwrE6tCIyHVOGjpCd6Ug9Hkky/MNHwKnWabL/4dy+pVvyFQE9iDuQPDRX+D55eGvfq1VUjmhfJ/VksJy6NHr/49P3tCvmIymZZdgfOgDrOsRj4Puc04OAnwsf+wvAjju24aR9tJqIb0f+Hd7mnYKx1Q3MLByBHpI6SFr6YjU94dDDZPe/ujhuFl5xMEgRoeuA2ScmTo7smJzbuZSHDJfT7qp6JHVb0mzrgAHnhBXObuMOO76v9q53xsA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=ILgRY5+Fz981rnHHgnY8pD7P4hJtorwPhDoWTapzONk=; b=wSed2XqVXB6aRf+IGxDEV1VsW7sjtn95MdRKZtXCyfp0Cr48E/1y8FxKe7pBjmSOhZTFMFHr+VZMvzXV/lbYABMgW6MmU7V3Gyw1mTKmaHawWAOjtAqOEdDjynqIo3NtfXxAizL8JZ0E8BGjMZ8uQdI4vej1r/0YoolfBCG+pqyFWi6aNRDnuS4oS6U+rHJ12RkRGZZbYC/8Xa9pRdL3m1Xto0yiT/oe4DT6vuw//5PIpIj7SV76QwuGfeZp6C/U+vnAGdlcu5jxcnrf6ZFXFXlKuAWwHXAsvj0VaoCP0ri/1eRs5erA3PU4uAzqj1VnBzrncSpd+2xG17nK4I+K0g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=ILgRY5+Fz981rnHHgnY8pD7P4hJtorwPhDoWTapzONk=; b=Vi/v6jlhexjk+DA0jaDVS4pvqgXoO9QmbAWo/XhR0gw+Zy5hYBZwEHcpPluYzqfqubvosypTWo5Hi4YT3+iFViLPualb0ZQI4h+sL66EloU9L2roHj6AMlkXJ7nqLH1ldwCJb74D+zmFSzxuwGyU7j/mKXvtL3zGksJUXaw4jSY= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from PH7PR12MB5685.namprd12.prod.outlook.com (2603:10b6:510:13c::22) by SJ0PR12MB6757.namprd12.prod.outlook.com (2603:10b6:a03:449::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9791.34; Fri, 10 Apr 2026 08:58:52 +0000 Received: from PH7PR12MB5685.namprd12.prod.outlook.com ([fe80::ce69:cfae:774d:a65c]) by PH7PR12MB5685.namprd12.prod.outlook.com ([fe80::ce69:cfae:774d:a65c%5]) with mapi id 15.20.9791.032; Fri, 10 Apr 2026 08:58:52 +0000 Message-ID: <2fae926b-a25b-42bc-ab63-caf36505b33d@amd.com> Date: Fri, 10 Apr 2026 10:58:47 +0200 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] dma-fence: Move signalling tracepoint to before ops detach To: Tvrtko Ursulin , Boris Brezillon Cc: dri-devel@lists.freedesktop.org, kernel-dev@igalia.com, Philipp Stanner , linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org References: <20260330133623.17704-1-tvrtko.ursulin@igalia.com> <20260331094944.772833c0@fedora> <918805b0-2cb9-454a-9048-84cc5bfc8798@igalia.com> Content-Language: en-US From: =?UTF-8?Q?Christian_K=C3=B6nig?= In-Reply-To: <918805b0-2cb9-454a-9048-84cc5bfc8798@igalia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: FR4P281CA0001.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:c8::15) To PH7PR12MB5685.namprd12.prod.outlook.com (2603:10b6:510:13c::22) Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5685:EE_|SJ0PR12MB6757:EE_ X-MS-Office365-Filtering-Correlation-Id: 3f0154d8-80ca-440c-5fa0-08de96df6334 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|22082099003|18002099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH7PR12MB5685.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014)(22082099003)(18002099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ZkFrdFBiNVFxVWFVRWh1RjdmNXlWQzVkNFRwV2JVb2hHM2M0SzJ0VE1yN3p0?= =?utf-8?B?VVBuSTJGUzEwRC9oeTFibkovT1NSRVhBUEMvUXVRa2orNGNOclNFc1E1dllK?= =?utf-8?B?cUtLcm1VOUJ4cFF4R3RHOE56SDJQUC82aFl4Y3dYVXVJZ1RuMS85bnRFOWM5?= =?utf-8?B?Y2RKQnJkNjRwL2dOVHowbWpHRDM4Ny9oVHBTeTNQbHVWQ2lwQktQSm9kM0gz?= =?utf-8?B?bTd1TUhnaXdqVlRLR1U3Vjl5YlpSRUFOSUc5S3dvbDF1MURXb1MvQjE0dlRL?= =?utf-8?B?aHQzYzNmREtaM2o1Wi8vVUEzb29lcEhhZ29wR0ZXVjE0WXlnZjBSaEFBWXpX?= =?utf-8?B?cjcvcG5FdGs4cXdJK0EyYzRtOS9BcUhZQmM5bEpISU1iQ0JXQU5ybW9lMm5h?= =?utf-8?B?WGJOcGR4M1NyRXZ2TUZ2T2xiUk9XWnBNSzdTZTg3ekl5OGxYVzN4WWtuL3VC?= =?utf-8?B?Z25pZytKbkNRZUZTbXV3WjRtWkFzTHFBSGk2RkdseVNNZHpOTTdZTUg3MTEw?= =?utf-8?B?cndZajkxdlV1QmM1d2czcVdXWmpaSXM5aVlNQThLL2ZEcGNzaGhPYXdnK2hn?= =?utf-8?B?QXdoUVZJUmQ1WHBtUUp6cnRRNExFTk4yckQwSElsa0NEMTlCZGJETGw5bElr?= =?utf-8?B?U1JTZHZONHdJeVlxRkRaL2hJcGVvOVU1Snp4aHBwOWZCellqVmlCaHB5dUlo?= =?utf-8?B?UkdmSzJmY2JYRHhrRmpuV2hjK1ZWci9CNldlUWZEVWxFRjRuZEJSYUNiU3hj?= =?utf-8?B?Z01LazFkK0tCQWVhWCtsN2R4aDhYaWJXZytuekZUMHRlM2JKdDdMbmEyTG9B?= =?utf-8?B?dXJITDJvK2N4ZThvZit3NGVqa0pBWUpVM0JydWczbDlwc2Z2NWVET0lFYW1F?= =?utf-8?B?NytlWE9YNytKdTZlN3dpbGgzODRScXZrQld2cnRESG1NcUFFTWg2OVA3dGlI?= =?utf-8?B?THhhejNlZU1RN1JCSEhKTTBWczN3T3hNU1FISWhwbWlzY3B6bzM5TkRzZ1E3?= =?utf-8?B?ejlJZ05GZEdnZXFTTG5ZL0dMay9mRFRONERycFVEbXhOTjV1TmZlMTFWYU1i?= =?utf-8?B?OVJBV1lhNGpRZXBTVXVsb1pZVHhMTDFRYU5hUFlFcVp0bGNIQXdMWklTS1dB?= =?utf-8?B?TzZ3TVhramZTQnNLRGpVdk1CbWlXYTYxd0Ivck5zSk9uRUdINnk4MnRVTDhr?= =?utf-8?B?dVhqeFl3bTcxSjM1UlExTW9qVzhqVW5pVm5ISXdBVmd5aGUxQnBqK2VXRTFP?= =?utf-8?B?eFVWWXJmREo3Vnl0dVlOTEM4UGczZ3ludVZuWmVYdGVRZTJYcXVnakg0akRh?= =?utf-8?B?K1B1SXVlOEM0dExsYkgwcm8xSmJlWE5jOHd2YWpjVVRWNno4ZGFqMHV2NzJt?= =?utf-8?B?VW44cTZ3ZGJtdS9Xc2hDU0ZTL3ZxQzNSdnFwdS9sb3ZRTUpNTWpJaFgrcGpu?= =?utf-8?B?VDA4NXd5VjREYXFpakxLc2ZyWjhHb2ZKRjlFLzFITUxYN2diem9KeDNScEF5?= =?utf-8?B?L0pjVDhIMWFoUzkzd0IvY01uUmN2bHpsRWFPT1BLS3ZVMU5OMnR2OWZ1SGJG?= =?utf-8?B?TDcrc1l3WDd4UTBmejc3UjRSakhOS2IyOU9qeW91cGNtaTdqNHdOcWxveUtQ?= =?utf-8?B?L3pqaE0wSkRwN01wY3dvazBwZVhGRjdETlVwY09mc0duUjdjMDhqdlBpYmhn?= =?utf-8?B?TVpMS3BjRDZaaWVELzBhSmFEZm0ycDVQb0xVTFZpdGFrSnBHYjRwZjJZMEw0?= =?utf-8?B?NHB3cWFsMVVONDNlQ0M2ZFJGb2ZRendsZkd6OFp3M3B2UWFjaVBHQUJUV0tB?= =?utf-8?B?VkkxYUxaOHVFU21ZZE1ZSWtuU3dLSW5rZ2loQkIzNEhVeVNMeTRQMzE0U2tP?= =?utf-8?B?RmJQOFhnZzZIckxHNHNNandxb2RzL1JYZU5BNFNzNitqKy9PUWFRbE5nSXlN?= =?utf-8?B?UjNuOUhkdWtKMjNWbDJyVHFBYmZBWlZ6L3J3N09SekgvVWZFMUNBTXZRcWVx?= =?utf-8?B?TG02eEhoRGhDYVc5Rm1PK280VXNyajhzNnN3Y0RUWVZTUjJjTWtvTmt1b1o4?= =?utf-8?B?MFV0NWZoMWJvNDZrYlVEUjZ2L3lJNWVkajREYVQ3Z1R5OVNXQzhWVEJkc0Fq?= =?utf-8?B?OWdxOEQ4VG4vS1U2OSs0REtVN2Y2S0wxVmdCMWFuNG5obVhpYXQxUnd0Tm5S?= =?utf-8?B?MlVaYUJTS0xLYmRybmlvUFQzczR4Q1M3ZjRYQXkyTGNFNzR6QkhaR3hNdnNL?= =?utf-8?B?clY2bUdlbHNHTnlXbm1BS3JpWjgrdGNHd3o5VGxTM1NodTB4TWVJL296NjVu?= =?utf-8?Q?cY/zpHlXm6477JIj62?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 3f0154d8-80ca-440c-5fa0-08de96df6334 X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5685.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Apr 2026 08:58:52.0869 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: L8amLVDQOszLaKY3VEyMlG8QqdUav34AXH9oNvZhikvT4SkFvuzazboO2/IIWao1 X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB6757 On 4/9/26 15:58, Tvrtko Ursulin wrote: > > On 31/03/2026 08:49, Boris Brezillon wrote: >> On Mon, 30 Mar 2026 14:36:23 +0100 >> Tvrtko Ursulin wrote: >> >>> Move the signalling tracepoint to before fence->ops are reset otherwise >>> tracepoint will dereference a null pointer. >> >> I suspect other trace points are impacted too >> (trace_dma_fence_destroy() is, at the very least). > > Indeed. I wonder why that did not trigger for me, while the one I fix here was an insta-crash... You need to actually enable the trace points and at least for the destroy one nobody is usually interested in that. > > To fix trace_dma_fence_destroy I think we need a new tracepoint definition ie. move it away from the existing event class - make it just log the context and seqno. > > Anyone has a better idea? The idea of tracing without accessing fence->ops sounds valid to me. Alternatively we could call dma_fence_timeline_name() and dma_fence_driver_name() from the tracepoint as well, but that means the tracepoints now require a RCU read side lock. Regards, Christian. > > Regards, > > Tvrtko > >>> Signed-off-by: Tvrtko Ursulin >>> Fixes: 541c8f2468b9 ("dma-buf: detach fence ops on signal v3") >>> Cc: Christian König >>> Cc: Philipp Stanner >>> Cc: Boris Brezillon >>> Cc: linux-media@vger.kernel.org >>> Cc: linaro-mm-sig@lists.linaro.org >>> --- >>>   drivers/dma-buf/dma-fence.c | 3 ++- >>>   1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c >>> index 1826ba73094c..1c1eaecaf1b0 100644 >>> --- a/drivers/dma-buf/dma-fence.c >>> +++ b/drivers/dma-buf/dma-fence.c >>> @@ -363,6 +363,8 @@ void dma_fence_signal_timestamp_locked(struct dma_fence *fence, >>>                         &fence->flags))) >>>           return; >>>   +    trace_dma_fence_signaled(fence); >>> + >>>       /* >>>        * When neither a release nor a wait operation is specified set the ops >>>        * pointer to NULL to allow the fence structure to become independent >>> @@ -377,7 +379,6 @@ void dma_fence_signal_timestamp_locked(struct dma_fence *fence, >>>         fence->timestamp = timestamp; >>>       set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags); >>> -    trace_dma_fence_signaled(fence); >>>         list_for_each_entry_safe(cur, tmp, &cb_list, node) { >>>           INIT_LIST_HEAD(&cur->node); >> >