Hi,

url:    
https://github.com/0day-ci/linux/commits/frowand-list-gmail-com/of-unittest-overlay-ensure-proper-alignment-of-copied-FDT/20210408-045317
 
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git  for-next
config: i386-randconfig-m021-20210407 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <l...@intel.com>
Reported-by: Dan Carpenter <dan.carpen...@oracle.com>

smatch warnings:
drivers/of/overlay.c:1045 of_overlay_fdt_apply() warn: overwrite may leak 
'new_fdt'

vim +/new_fdt +1045 drivers/of/overlay.c

39a751a4cb7e47 Frank Rowand      2018-02-12  1015  int 
of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size,
39a751a4cb7e47 Frank Rowand      2018-02-12  1016                        int 
*ovcs_id)
39a751a4cb7e47 Frank Rowand      2018-02-12  1017  {
7a18fbf9013a19 Frank Rowand      2021-04-07  1018       void *new_fdt;
39a751a4cb7e47 Frank Rowand      2018-02-12  1019       int ret;
39a751a4cb7e47 Frank Rowand      2018-02-12  1020       u32 size;
39a751a4cb7e47 Frank Rowand      2018-02-12  1021       struct device_node 
*overlay_root;
39a751a4cb7e47 Frank Rowand      2018-02-12  1022  
39a751a4cb7e47 Frank Rowand      2018-02-12  1023       *ovcs_id = 0;
39a751a4cb7e47 Frank Rowand      2018-02-12  1024       ret = 0;
39a751a4cb7e47 Frank Rowand      2018-02-12  1025  
39a751a4cb7e47 Frank Rowand      2018-02-12  1026       if (overlay_fdt_size < 
sizeof(struct fdt_header) ||
39a751a4cb7e47 Frank Rowand      2018-02-12  1027           
fdt_check_header(overlay_fdt)) {
39a751a4cb7e47 Frank Rowand      2018-02-12  1028               pr_err("Invalid 
overlay_fdt header\n");
39a751a4cb7e47 Frank Rowand      2018-02-12  1029               return -EINVAL;
39a751a4cb7e47 Frank Rowand      2018-02-12  1030       }
39a751a4cb7e47 Frank Rowand      2018-02-12  1031  
39a751a4cb7e47 Frank Rowand      2018-02-12  1032       size = 
fdt_totalsize(overlay_fdt);
39a751a4cb7e47 Frank Rowand      2018-02-12  1033       if (overlay_fdt_size < 
size)
39a751a4cb7e47 Frank Rowand      2018-02-12  1034               return -EINVAL;
39a751a4cb7e47 Frank Rowand      2018-02-12  1035  
39a751a4cb7e47 Frank Rowand      2018-02-12  1036       /*
39a751a4cb7e47 Frank Rowand      2018-02-12  1037        * Must create 
permanent copy of FDT because of_fdt_unflatten_tree()
39a751a4cb7e47 Frank Rowand      2018-02-12  1038        * will create pointers 
to the passed in FDT in the unflattened tree.
39a751a4cb7e47 Frank Rowand      2018-02-12  1039        */
7a18fbf9013a19 Frank Rowand      2021-04-07  1040       size += FDT_ALIGN_SIZE;
7a18fbf9013a19 Frank Rowand      2021-04-07  1041       new_fdt = kmalloc(size, 
GFP_KERNEL);
39a751a4cb7e47 Frank Rowand      2018-02-12  1042       if (!new_fdt)
39a751a4cb7e47 Frank Rowand      2018-02-12  1043               return -ENOMEM;
39a751a4cb7e47 Frank Rowand      2018-02-12  1044  
7a18fbf9013a19 Frank Rowand      2021-04-07 @1045       new_fdt = 
PTR_ALIGN(new_fdt, FDT_ALIGN_SIZE);
                                                        ^^^^^^^
We're not freeing the exact same pointer that we allocated.

7a18fbf9013a19 Frank Rowand      2021-04-07  1046       memcpy(new_fdt, 
overlay_fdt, size);
7a18fbf9013a19 Frank Rowand      2021-04-07  1047  
39a751a4cb7e47 Frank Rowand      2018-02-12  1048       
of_fdt_unflatten_tree(new_fdt, NULL, &overlay_root);
39a751a4cb7e47 Frank Rowand      2018-02-12  1049       if (!overlay_root) {
39a751a4cb7e47 Frank Rowand      2018-02-12  1050               pr_err("unable 
to unflatten overlay_fdt\n");
39a751a4cb7e47 Frank Rowand      2018-02-12  1051               ret = -EINVAL;
39a751a4cb7e47 Frank Rowand      2018-02-12  1052               goto 
out_free_new_fdt;
39a751a4cb7e47 Frank Rowand      2018-02-12  1053       }
39a751a4cb7e47 Frank Rowand      2018-02-12  1054  
39a751a4cb7e47 Frank Rowand      2018-02-12  1055       ret = 
of_overlay_apply(new_fdt, overlay_root, ovcs_id);
39a751a4cb7e47 Frank Rowand      2018-02-12  1056       if (ret < 0) {
39a751a4cb7e47 Frank Rowand      2018-02-12  1057               /*
39a751a4cb7e47 Frank Rowand      2018-02-12  1058                * new_fdt and 
overlay_root now belong to the overlay
39a751a4cb7e47 Frank Rowand      2018-02-12  1059                * changeset.
39a751a4cb7e47 Frank Rowand      2018-02-12  1060                * overlay 
changeset code is responsible for freeing them.
39a751a4cb7e47 Frank Rowand      2018-02-12  1061                */
39a751a4cb7e47 Frank Rowand      2018-02-12  1062               goto out;
39a751a4cb7e47 Frank Rowand      2018-02-12  1063       }
39a751a4cb7e47 Frank Rowand      2018-02-12  1064  
39a751a4cb7e47 Frank Rowand      2018-02-12  1065       return 0;
39a751a4cb7e47 Frank Rowand      2018-02-12  1066  
39a751a4cb7e47 Frank Rowand      2018-02-12  1067  
39a751a4cb7e47 Frank Rowand      2018-02-12  1068  out_free_new_fdt:
39a751a4cb7e47 Frank Rowand      2018-02-12  1069       kfree(new_fdt);
39a751a4cb7e47 Frank Rowand      2018-02-12  1070  
39a751a4cb7e47 Frank Rowand      2018-02-12  1071  out:
39a751a4cb7e47 Frank Rowand      2018-02-12  1072       return ret;
39a751a4cb7e47 Frank Rowand      2018-02-12  1073  }

---
0-DAY CI Kernel Test Service, Intel Corporation
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