Re: [PATCH v2 2/8] media: videobuf2: Make bufs array dynamic allocated

From: Dan Carpenter <error27@gmail.com>
To: oe-kbuild@lists.linux.dev,
	Benjamin Gaignard <benjamin.gaignard@collabora.com>,
	tfiga@chromium.org, m.szyprowski@samsung.com, mchehab@kernel.org,
	ming.qian@nxp.com, shijie.qin@nxp.com, eagle.zhou@nxp.com,
	bin.liu@mediatek.com, matthias.bgg@gmail.com,
	angelogioacchino.delregno@collabora.com,
	tiffany.lin@mediatek.com, andrew-ct.chen@mediatek.com,
	yunfei.dong@mediatek.com, stanimir.k.varbanov@gmail.com,
	quic_vgarodia@quicinc.com, agross@kernel.org,
	andersson@kernel.org, konrad.dybcio@linaro.org,
	ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de,
	daniel.almeida@collabora.com, hverkuil-cisco@xs4all.nl,
	laurent.pinchart@ideasonboard.com, jernel@kernel.org
Cc: lkp@intel.com, oe-kbuild-all@lists.linux.dev,
	linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-msm@vger.kernel.org,
	linux-rockchip@lists.infradead.org, kernel@collabora.com
Subject: Re: [PATCH v2 2/8] media: videobuf2: Make bufs array dynamic allocated
Date: Fri, 24 Mar 2023 08:01:09 +0300	[thread overview]
Message-ID: <4e2cb832-de83-4ba6-bd8a-119a19038cfe@kili.mountain> (raw)
In-Reply-To: <20230321102855.346732-3-benjamin.gaignard@collabora.com>

Hi Benjamin,

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Benjamin-Gaignard/media-videobuf2-Access-vb2_queue-bufs-array-through-helper-functions/20230321-183154
base:   git://linuxtv.org/media_tree.git master
patch link:    https://lore.kernel.org/r/20230321102855.346732-3-benjamin.gaignard%40collabora.com
patch subject: [PATCH v2 2/8] media: videobuf2: Make bufs array dynamic allocated
config: arm64-randconfig-m041-20230319 (https://download.01.org/0day-ci/archive/20230324/202303240148.lKRnUqW9-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 12.1.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Link: https://lore.kernel.org/r/202303240148.lKRnUqW9-lkp@intel.com/

smatch warnings:
include/media/videobuf2-core.h:1272 vb2_queue_add_buffer() warn: sleeping in atomic context
drivers/media/common/videobuf2/videobuf2-core.c:2456 vb2_core_queue_init() warn: Please consider using kcalloc instead of kmalloc_array

vim +1272 include/media/videobuf2-core.h

625d46c1c1fe8e Benjamin Gaignard 2023-03-21  1263  static inline bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb)
625d46c1c1fe8e Benjamin Gaignard 2023-03-21  1264  {
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1265  	bool ret = false;
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1266  
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1267  	spin_lock(&q->bufs_lock);
                                                        ^^^^^^^^^^^^^^^^^^^^^^^
Holding a spin lock.

487d3f14d12ecf Benjamin Gaignard 2023-03-21  1268  
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1269  	if (vb->index >= q->max_num_bufs) {
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1270  		struct vb2_buffer **tmp;
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1271  
487d3f14d12ecf Benjamin Gaignard 2023-03-21 @1272  		tmp = krealloc_array(q->bufs, q->max_num_bufs * 2, sizeof(*q->bufs), GFP_KERNEL);
                                                                                                                                     ^^^^^^^^^^
Sleeping allocation.  GFP_ATOMIC?  Or is there a way to move the
allocation outside the lock?

487d3f14d12ecf Benjamin Gaignard 2023-03-21  1273  		if (!tmp)
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1274  			goto realloc_failed;
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1275  
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1276  		q->max_num_bufs *= 2;
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1277  		q->bufs = tmp;
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1278  	}
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1279  
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1280  	if (vb->index < q->max_num_bufs) {
625d46c1c1fe8e Benjamin Gaignard 2023-03-21  1281  		q->bufs[vb->index] = vb;
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1282  		ret = true;
625d46c1c1fe8e Benjamin Gaignard 2023-03-21  1283  	}
625d46c1c1fe8e Benjamin Gaignard 2023-03-21  1284  
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1285  realloc_failed:
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1286  	spin_unlock(&q->bufs_lock);
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1287  
487d3f14d12ecf Benjamin Gaignard 2023-03-21  1288  	return ret;
625d46c1c1fe8e Benjamin Gaignard 2023-03-21  1289  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests