Received-SPF: pass (google.com: domain of linux-kernel+bounces-191029-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
Message-ID: <b25747ca-c8a8-45de-a5e1-f8cf2caa2729@amd.com>
Date: Mon, 27 May 2024 17:01:51 +0200
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v2] dma-buf: handle testing kthreads creation failure
To: "T.J. Mercier" <tjmercier@google.com>, Fedor Pchelkin <pchelkin@ispras.ru>
Cc: Sumit Semwal <sumit.semwal@linaro.org>,
 Chris Wilson <chris@chris-wilson.co.uk>,
 Daniel Vetter <daniel.vetter@ffwll.ch>, linux-media@vger.kernel.org,
 dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
 linux-kernel@vger.kernel.org, Alexey Khoroshilov <khoroshilov@ispras.ru>,
 lvc-project@linuxtesting.org, stable@vger.kernel.org
References: <20240522181308.841686-1-pchelkin@ispras.ru>
 <CABdmKX2qdT0HvkX0B6kcxALwxZsLFOtgPsOP_rY0AXM1eAtAtA@mail.gmail.com>
Content-Language: en-US
From: =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>
In-Reply-To: <CABdmKX2qdT0HvkX0B6kcxALwxZsLFOtgPsOP_rY0AXM1eAtAtA@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?utf-8?B?RmNWZjZMVkRmbmc1YWNPeHBKeG1oREN1UHF5eFdGQ0V1TTN4dDQ0NXdoTFhs?=
 =?utf-8?B?Y2szZTFRdWhvTjR4dUk2QU9kZTBDeTcrcmp1UGlzdjN4alJrS0g5N3Zid2J4?=
 =?utf-8?B?S3AxVVg0Q0RsM1FUWkhtSFIrbmRSejMvcEFXK20rZFFqcEh0UFdkYnkzTHZK?=
 =?utf-8?B?MklFRkJ5WVB5SG9hTHJpeHU0T29XQzhTdUdXMU9md0lnUGlTTUJYNXRYa2My?=
 =?utf-8?B?SGlLc0RaYXBtZWlPOTIvSWRORWZsWUk0ZlFONTBlaFhHWWt3WjdRZURBRnhJ?=
 =?utf-8?B?SEsrbDg4Y3c4UUJzbDFlU0ZvWXBlMzFVWEpxOUN1bTRyMEtSTVdjeTUrZ2hW?=
 =?utf-8?B?dFJINHZNbDlaWWRSTk13bnl0Y25mbHNoZEx4M1RTc1J6eURNekZUMmtIbVNy?=
 =?utf-8?B?Sk5HZkE3YkhIM1M1K3cwTDFTSUVpMTd1Z0x2RkFMWGk3MFF1eTFLejRCazZD?=
 =?utf-8?B?U3JoRUpHeE8xdW1iczNNbzdjV0VrbmJlc3dqSnlzSzJCdWJiNXFRMFBldkps?=
 =?utf-8?B?WC9vdDY4YUFNbEp6cHptNGdtcjloQXF2bUdXd2RBbVU5dzhjYW1LUmF2NUV2?=
 =?utf-8?B?TUtRN3A4Njg3amNzV3VRL2paNTB6dlluUit3UVlZcHZQYTY5bzZidmVaYlBI?=
 =?utf-8?B?UlZvS2VkT2RYWm9uaUY5aUtBL21YRVMvTlJ2WldzQ1A2MFFLbXl6UnVONFc2?=
 =?utf-8?B?cDM5enVwcjNTaDJVUDZGTXFIbkc0Q0V6ZDQ1K2lKSDBVQUlHcTZwNGdzdE9G?=
 =?utf-8?B?WUtleTV3OVVQSE04K0xtbGpra290Q011L3F3OFkzUWlNdGJ1SkFKdWc5MStK?=
 =?utf-8?B?eFpON2hnbUorL0NwRW9PMTlMYkgvdkc0RFNndm5RV2ZFTVZsK0RQZm9zOTJl?=
 =?utf-8?B?UStnbFlCSWxrdER3ekdVTE1XMFZ6UmtwV2JKNzNmZDBlbFJVTDNTQyt5R2Z3?=
 =?utf-8?B?WHhPMC8zUGpEdzVwbmxmQjUrYUVUa0o5MVExL3NzWnNsT0FjbGtTZXdSRmdH?=
 =?utf-8?B?bTh0WjkwU0J0bmFtU3pscW05RVZ2Y2RuWnhZQm1rVTFXczhSc0JMQXQ5TjR1?=
 =?utf-8?B?S3dnMlpDKzhueHJObWp4R0xnaXRJYWZ1b1lvS09XWFJzRkRZaW1XbGh4VXRB?=
 =?utf-8?B?UnhuSTVlT2RUalRKMHNIenYzdE80SGxSdWhrOG9LU1pEK0EzMmM3RWRXa3hX?=
 =?utf-8?B?RWpaSzQ3NGljYy9MNlRYeXdQUDB0dDllNm5pR3pQbVJtbEZYc0ZuYU9DM3RP?=
 =?utf-8?B?VlR5SE1SYWdCNnJ3MU1wYTlGT2N2V0VUaG0waDZWREdnNkNHckNwSGlYemJ4?=
 =?utf-8?B?MjVaNUZnajZuNDgrNC9TOC9HVm84YVFZelpWa2tKQUFoNmR6M1NRRHdlZWpX?=
 =?utf-8?B?Y05zOUFkWkc2YWxHaXU1SFBtYWZUZUhBSG9jaWtqcEZOVmxpUjNHdVhoNVFL?=
 =?utf-8?B?OTNnRzdkekFrV0ZRQzJ5M2I0Z3QrZk8zd2RZN01Ka3N2U2I4ekQ1dEF6dklO?=
 =?utf-8?B?eStqeVBRV3JjTEkxNlp6eG5lUm5jN3Y4UzFxNVprTFE4cFBkNkdnYWV4dTlF?=
 =?utf-8?B?RVJKQ25BNkk1aS9wdUo0Zkc0anA0c2hjTnRtbndzK01FM09NMUdOKzJ6SFhO?=
 =?utf-8?B?VmhYYVlBUFo0RUkxNVo3UlQvOGhsNmN2QWJNNU9TWjFjYmxYZ1VMbUEyaG43?=
 =?utf-8?B?enRmTFJpWGNZRnpiR1dtT1FHZG1sZHFaRDhsbEVPZHFNdXNTaWhDRmIwQ3o3?=
 =?utf-8?B?bFViWG5EVXRZQnVWbEJZOWQ1TUtJUi95RWdRbVZjWDVSa3ZMdElRRStDV1Y4?=
 =?utf-8?B?dS9GNzdiZlJib3lqZ0p6NnRST05vL080bnBzb3RWVG5lNG1UZ3FPT3E0Z1Jp?=
 =?utf-8?B?cm0wLy9kMFUvalkzN1l1WThNNXd4dFQ1aVd1WlRpejRXY09NWVg4NENjUHlw?=
 =?utf-8?B?cVRiaTVjNHA2bFZKT3BOQWpvVWhMY3orUE12dlhHRDk2UzRwZGhLTHM0eTI0?=
 =?utf-8?B?MDRRMzRabGw0amowb240N0V3aUVpTXlSRVlOTE5ZZ2JWUWdrRkRSR0FhZmxt?=
 =?utf-8?B?aVlUeG9BeWhTODMrMmkwWU5UQjIxSFNKaDdENVpXNFdWK2R1ZitaV2ErNHJR?=
 =?utf-8?Q?+AwM=3D?=
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-Network-Message-Id: c6f0c941-3819-4a2b-2e5f-08dc7e5df47c
X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5685.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 May 2024 15:01:58.1988
 (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: ndf87bHWmbeoo8fms5x6zL+njUZvOS8UCgdFcagMOPDpMLuvtU5R+J6iY/lLe5ni
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB6699

Am 22.05.24 um 20:33 schrieb T.J. Mercier:
> On Wed, May 22, 2024 at 11:14 AM Fedor Pchelkin <pchelkin@ispras.ru> wrote:
>> kthread creation may possibly fail inside race_signal_callback(). In
>> such a case stop the already started threads, put the already taken
>> references to them and return with error code.
>>
>> Found by Linux Verification Center (linuxtesting.org).
>>
>> Fixes: 2989f6451084 ("dma-buf: Add selftests for dma-fence")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> Reviewed-by: T.J. Mercier <tjmercier@google.com>

Just FYI: I've picked this one up and pushed it to drm-misc-fixes.

Regards,
Christian.

>> ---
>> v2: use kthread_stop_put() to actually put the last reference as
>>      T.J. Mercier noticed;
>>      link to v1: https://lore.kernel.org/lkml/20240522122326.696928-1-pchelkin@ispras.ru/
>>
>>   drivers/dma-buf/st-dma-fence.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/dma-buf/st-dma-fence.c b/drivers/dma-buf/st-dma-fence.c
>> index b7c6f7ea9e0c..6a1bfcd0cc21 100644
>> --- a/drivers/dma-buf/st-dma-fence.c
>> +++ b/drivers/dma-buf/st-dma-fence.c
>> @@ -540,6 +540,12 @@ static int race_signal_callback(void *arg)
>>                          t[i].before = pass;
>>                          t[i].task = kthread_run(thread_signal_callback, &t[i],
>>                                                  "dma-fence:%d", i);
>> +                       if (IS_ERR(t[i].task)) {
>> +                               ret = PTR_ERR(t[i].task);
>> +                               while (--i >= 0)
>> +                                       kthread_stop_put(t[i].task);
>> +                               return ret;
>> +                       }
>>                          get_task_struct(t[i].task);
>>                  }
>>
>> --
>> 2.39.2
>>