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

[yangxingui]

On 2024/3/11 13:42, Dan Carpenter wrote:
> 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.

Yes, it's possible. This patch has been canceled in v4. Based on John's 
suggestion, if there are plans to resubmit modifications , we will pay 
attention to this, thank you.

Thanks,
Xingui