Subject: Re: [PATCH] net/802: use struct_size over open coded arithmetic

From: kernel test robot <[email-masked]>
Date: Fri, 28 Jan 2022 20:40:51 +0800

Hi,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on net-next/master]
[also build test ERROR on net/master horms-ipvs/master linus/master v5.17-rc1 next-20220128]
[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]

url:    https://github.com/0day-ci/linux/commits/cgel-zte-gmail-com/net-802-use-struct_size-over-open-coded-arithmetic/20220128-160925
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 72d044e4bfa6bd9096536e2e1c62aecfe1a525e4
config: riscv-randconfig-r042-20220124 (https://download.01.org/0day-ci/archive/20220128/[email-masked]/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 33b45ee44b1f32ffdbc995e6fec806271b4b3ba4)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/0day-ci/linux/commit/9b64e5078d3d779fc56432d43129479f63996c74
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review cgel-zte-gmail-com/net-802-use-struct_size-over-open-coded-arithmetic/20220128-160925
        git checkout 9b64e5078d3d779fc56432d43129479f63996c74
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/net/wireless/ath/wcn36xx/ net/802/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email-masked]>

All errors (new ones prefixed by >>):

>> net/802/garp.c:187:17: error: member reference type 'struct garp_attr' is not a pointer; did you mean to use '.'?
           attr = kmalloc(struct_size(*attr, data, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:18: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                               ~~~^
>> net/802/garp.c:187:17: error: indirection requires pointer operand ('unsigned char[]' invalid)
           attr = kmalloc(struct_size(*attr, data, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:14: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                              ^~~~~~~~~~~~
>> net/802/garp.c:187:17: error: member reference type 'struct garp_attr' is not a pointer; did you mean to use '.'?
           attr = kmalloc(struct_size(*attr, data, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:49: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                                              ~~~~~~~~~~~~~~~~~~~^~~~~~~~~
   include/linux/compiler.h:258:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
   include/linux/compiler_types.h:287:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
>> net/802/garp.c:187:17: error: member reference type 'struct garp_attr' is not a pointer; did you mean to use '.'?
           attr = kmalloc(struct_size(*attr, data, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:49: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                                              ~~~~~~~~~~~~~~~~~~~^~~~~~~~~
   include/linux/compiler.h:258:65: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
   include/linux/compiler_types.h:287:74: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                            ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
>> net/802/garp.c:187:17: error: indirection requires pointer operand ('struct garp_attr' invalid)
           attr = kmalloc(struct_size(*attr, data, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:195:14: note: expanded from macro 'struct_size'
                       sizeof(*(p)))
                              ^~~~
   5 errors generated.
--
>> net/802/mrp.c:276:17: error: member reference type 'struct mrp_attr' is not a pointer; did you mean to use '.'?
           attr = kmalloc(struct_size(*attr, value, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:18: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                               ~~~^
>> net/802/mrp.c:276:17: error: indirection requires pointer operand ('unsigned char[]' invalid)
           attr = kmalloc(struct_size(*attr, value, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:14: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                              ^~~~~~~~~~~~
>> net/802/mrp.c:276:17: error: member reference type 'struct mrp_attr' is not a pointer; did you mean to use '.'?
           attr = kmalloc(struct_size(*attr, value, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:49: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                                              ~~~~~~~~~~~~~~~~~~~^~~~~~~~~
   include/linux/compiler.h:258:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
   include/linux/compiler_types.h:287:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
>> net/802/mrp.c:276:17: error: member reference type 'struct mrp_attr' is not a pointer; did you mean to use '.'?
           attr = kmalloc(struct_size(*attr, value, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:194:49: note: expanded from macro 'struct_size'
                       sizeof(*(p)->member) + __must_be_array((p)->member),\
                                              ~~~~~~~~~~~~~~~~~~~^~~~~~~~~
   include/linux/compiler.h:258:65: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
   include/linux/compiler_types.h:287:74: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                            ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
>> net/802/mrp.c:276:17: error: indirection requires pointer operand ('struct mrp_attr' invalid)
           attr = kmalloc(struct_size(*attr, value, len), GFP_ATOMIC);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:195:14: note: expanded from macro 'struct_size'
                       sizeof(*(p)))
                              ^~~~
   5 errors generated.

vim +187 net/802/garp.c

   166	
   167	static struct garp_attr *garp_attr_create(struct garp_applicant *app,
   168						  const void *data, u8 len, u8 type)
   169	{
   170		struct rb_node *parent = NULL, **p = &app->gid.rb_node;
   171		struct garp_attr *attr;
   172		int d;
   173	
   174		while (*p) {
   175			parent = *p;
   176			attr = rb_entry(parent, struct garp_attr, node);
   177			d = garp_attr_cmp(attr, data, len, type);
   178			if (d > 0)
   179				p = &parent->rb_left;
   180			else if (d < 0)
   181				p = &parent->rb_right;
   182			else {
   183				/* The attribute already exists; re-use it. */
   184				return attr;
   185			}
   186		}
 > 187		attr = kmalloc(struct_size(*attr, data, len), GFP_ATOMIC);
   188		if (!attr)
   189			return attr;
   190		attr->state = GARP_APPLICANT_VO;
   191		attr->type  = type;
   192		attr->dlen  = len;
   193		memcpy(attr->data, data, len);
   194	
   195		rb_link_node(&attr->node, parent, p);
   196		rb_insert_color(&attr->node, &app->gid);
   197		return attr;
   198	}
   199	

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