Re: [PATCH v3 1/3] scsi: libsas: Allow smp_execute_task() arguments to be on the stack

[Dan Carpenter]

Hi Xingui,

kernel test robot noticed the following build warnings:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Xingui-Yang/scsi-libsas-Allow-smp_execute_task-arguments-to-be-on-the-stack/20240307-174215
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git for-next
patch link:    https://lore.kernel.org/r/20240307093733.41222-2-yangxingui%40huawei.com
patch subject: [PATCH v3 1/3] scsi: libsas: Allow smp_execute_task() arguments to be on the stack
config: i386-randconfig-141-20240308 (https://download.01.org/0day-ci/archive/20240310/202403102353.jUPi6fOP-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0

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@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202403102353.jUPi6fOP-lkp@xxxxxxxxx/

New smatch warnings:
drivers/scsi/libsas/sas_expander.c:148 smp_execute_task() warn: possible memory leak of '_req'

vim +/_req +148 drivers/scsi/libsas/sas_expander.c

adfd2325dfc5cf6 Xingui Yang     2024-03-07  138  static int smp_execute_task(struct domain_device *dev, void *req, int req_size,
adfd2325dfc5cf6 Xingui Yang     2024-03-07  139  			    void *resp, int resp_size)
adfd2325dfc5cf6 Xingui Yang     2024-03-07  140  {
adfd2325dfc5cf6 Xingui Yang     2024-03-07  141  	struct scatterlist req_sg;
adfd2325dfc5cf6 Xingui Yang     2024-03-07  142  	struct scatterlist resp_sg;
adfd2325dfc5cf6 Xingui Yang     2024-03-07  143  	void *_req = kmemdup(req, req_size, GFP_KERNEL);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  144  	void *_resp = alloc_smp_resp(resp_size);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  145  	int ret;
adfd2325dfc5cf6 Xingui Yang     2024-03-07  146  
adfd2325dfc5cf6 Xingui Yang     2024-03-07  147  	if (!_req || !resp)
adfd2325dfc5cf6 Xingui Yang     2024-03-07 @148  		return -ENOMEM;

I haven't looked at the callers so I don't know how likely it is for one
of the allocations to fail and the other succeed...  But it seems
possible.

adfd2325dfc5cf6 Xingui Yang     2024-03-07  149  
adfd2325dfc5cf6 Xingui Yang     2024-03-07  150  	sg_init_one(&req_sg, _req, req_size);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  151  	sg_init_one(&resp_sg, _resp, resp_size);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  152  	ret = smp_execute_task_sg(dev, &req_sg, &resp_sg);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  153  	memcpy(resp, _resp, resp_size);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  154  	kfree(_req);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  155  	kfree(_resp);
adfd2325dfc5cf6 Xingui Yang     2024-03-07  156  	return ret;
adfd2325dfc5cf6 Xingui Yang     2024-03-07  157  }

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