linux-kernel - Re: [PATCH] kernel memory safety check in a block

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Message-ID: <202510301541.ExxRSMBP-lkp@intel.com>
Date: Thu, 30 Oct 2025 16:37:35 +0800
From: kernel test robot <lkp@...el.com>
To: Biancaa Ramesh <biancaa2210329@....edu.in>,
	linux-kernel@...r.kernel.org
Cc: oe-kbuild-all@...ts.linux.dev, awalls@...metrocast.net,
	mchehab@...nel.org, linux-media@...r.kernel.org,
	Biancaa Ramesh <biancaa2210329@....edu.in>
Subject: Re: [PATCH] kernel memory safety check in a block

Hi Biancaa,

kernel test robot noticed the following build warnings:

[auto build test WARNING on sailus-media-tree/master]
[also build test WARNING on linus/master v6.18-rc3 next-20251029]
[cannot apply to sailus-media-tree/streams]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Biancaa-Ramesh/kernel-memory-safety-check-in-a-block/20251022-041827
base:   git://linuxtv.org/sailus/media_tree.git master
patch link:    https://lore.kernel.org/r/20251021201704.178535-1-biancaa2210329%40ssn.edu.in
patch subject: [PATCH] kernel memory safety check in a block
config: um-randconfig-r073-20251025 (https://download.01.org/0day-ci/archive/20251030/202510301541.ExxRSMBP-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project e1ae12640102fd2b05bc567243580f90acb1135f)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510301541.ExxRSMBP-lkp@intel.com/

New smatch warnings:
drivers/media/pci/cx18/cx18-queue.c:389 cx18_stream_alloc() warn: inconsistent indenting

Old smatch warnings:
drivers/media/pci/cx18/cx18-queue.c:392 cx18_stream_alloc() warn: inconsistent indenting

vim +389 drivers/media/pci/cx18/cx18-queue.c

   331	
   332	int cx18_stream_alloc(struct cx18_stream *s)
   333	{
   334		struct cx18 *cx = s->cx;
   335		int i;
   336	
   337		if (s->buffers == 0)
   338			return 0;
   339	
   340		CX18_DEBUG_INFO("Allocate %s stream: %d x %d buffers (%d.%02d kB total)\n",
   341			s->name, s->buffers, s->buf_size,
   342			s->buffers * s->buf_size / 1024,
   343			(s->buffers * s->buf_size * 100 / 1024) % 100);
   344	
   345		if (((char __iomem *)&cx->scb->cpu_mdl[cx->free_mdl_idx + s->buffers] -
   346					(char __iomem *)cx->scb) > SCB_RESERVED_SIZE) {
   347			unsigned bufsz = (((char __iomem *)cx->scb) + SCB_RESERVED_SIZE -
   348						((char __iomem *)cx->scb->cpu_mdl));
   349	
   350			CX18_ERR("Too many buffers, cannot fit in SCB area\n");
   351			CX18_ERR("Max buffers = %zu\n",
   352				bufsz / sizeof(struct cx18_mdl_ent));
   353			return -ENOMEM;
   354		}
   355	
   356		s->mdl_base_idx = cx->free_mdl_idx;
   357	
   358		/* allocate stream buffers and MDLs */
   359		for (i = 0; i < s->buffers; i++) {
   360			struct cx18_mdl *mdl;
   361			struct cx18_buffer *buf;
   362	
   363			/* 1 MDL per buffer to handle the worst & also default case */
   364			mdl = kzalloc(sizeof(struct cx18_mdl), GFP_KERNEL|__GFP_NOWARN);
   365			if (mdl == NULL)
   366				break;
   367	
   368			buf = kzalloc(sizeof(struct cx18_buffer),
   369					GFP_KERNEL|__GFP_NOWARN);
   370			if (buf == NULL) {
   371				kfree(mdl);
   372				break;
   373			}
   374	
   375			buf->buf = kmalloc(s->buf_size, GFP_KERNEL|__GFP_NOWARN);
   376			if (buf->buf == NULL) {
   377				kfree(mdl);
   378				kfree(buf);
   379				break;
   380			}
   381	
   382			buf->dma_handle = dma_map_single(&s->cx->pci_dev->dev,
   383							 buf->buf, s->buf_size,
   384							 s->dma);
   385			if (dma_mapping_error(&s->cx->pci_dev->dev, buf->dma_handle)) {
   386				if (buf) {
   387	        		if (buf->buf){
   388	            	kfree(buf->buf);
 > 389					buf->buf =NULL;
   390					}
   391	        		kfree(buf);
   392					buf=NULL;
   393	    		}
   394				kfree(mdl);
   395				//makes accidental double free less possible
   396				break;
   397			}
   398	
   399			INIT_LIST_HEAD(&mdl->list);
   400			INIT_LIST_HEAD(&mdl->buf_list);
   401			mdl->id = s->mdl_base_idx; /* a somewhat safe value */
   402			cx18_enqueue(s, mdl, &s->q_idle);
   403	
   404			INIT_LIST_HEAD(&buf->list);
   405			cx18_buf_sync_for_cpu(s, buf);
   406			list_add_tail(&buf->list, &s->buf_pool);
   407		}
   408		if (i == s->buffers) {
   409			cx->free_mdl_idx += s->buffers;
   410			return 0;
   411		}
   412		CX18_ERR("Couldn't allocate buffers for %s stream\n", s->name);
   413		cx18_stream_free(s);
   414		return -ENOMEM;
   415	}
   416	

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