Re: [PATCH] fortify: Use WARN instead of BUG for now

[kbuild test robot]

Hi Kees,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.13-rc2 next-20170726]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Kees-Cook/fortify-Use-WARN-instead-of-BUG-for-now/20170727-101839
config: i386-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   In file included from arch/x86/include/asm/page_32.h:34:0,
                    from arch/x86/include/asm/page.h:13,
                    from arch/x86/include/asm/thread_info.h:11,
                    from include/linux/thread_info.h:37,
                    from arch/x86/include/asm/preempt.h:6,
                    from include/linux/preempt.h:80,
                    from include/linux/spinlock.h:50,
                    from include/linux/wait.h:8,
                    from include/linux/wait_bit.h:7,
                    from include/linux/fs.h:5,
                    from include/linux/buffer_head.h:11,
                    from fs/adfs/dir_f.c:12:
   In function 'memcpy',
       inlined from '__adfs_dir_put' at fs/adfs/dir_f.c:318:2,
       inlined from 'adfs_f_update' at fs/adfs/dir_f.c:403:2:
>> include/linux/string.h:308:4: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
       __read_overflow2();
       ^~~~~~~~~~~~~~~~~~

vim +/__read_overflow2 +308 include/linux/string.h

6974f0c4 Daniel Micay 2017-07-12  299  
6974f0c4 Daniel Micay 2017-07-12  300  __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
6974f0c4 Daniel Micay 2017-07-12  301  {
6974f0c4 Daniel Micay 2017-07-12  302  	size_t p_size = __builtin_object_size(p, 0);
6974f0c4 Daniel Micay 2017-07-12  303  	size_t q_size = __builtin_object_size(q, 0);
6974f0c4 Daniel Micay 2017-07-12  304  	if (__builtin_constant_p(size)) {
6974f0c4 Daniel Micay 2017-07-12  305  		if (p_size < size)
6974f0c4 Daniel Micay 2017-07-12  306  			__write_overflow();
6974f0c4 Daniel Micay 2017-07-12  307  		if (q_size < size)
6974f0c4 Daniel Micay 2017-07-12 @308  			__read_overflow2();
acf23d09 Kees Cook    2017-07-25  309  	} else {
acf23d09 Kees Cook    2017-07-25  310  		if (p_size < size)
acf23d09 Kees Cook    2017-07-25  311  			fortify_write_overflow(__func__);
acf23d09 Kees Cook    2017-07-25  312  		if (q_size < size)
acf23d09 Kees Cook    2017-07-25  313  			fortify_read_overflow2(__func__);
6974f0c4 Daniel Micay 2017-07-12  314  	}
6974f0c4 Daniel Micay 2017-07-12  315  	return __builtin_memcpy(p, q, size);
6974f0c4 Daniel Micay 2017-07-12  316  }
6974f0c4 Daniel Micay 2017-07-12  317  

:::::: The code at line 308 was first introduced by commit
:::::: 6974f0c4555e285ab217cee58b6e874f776ff409 include/linux/string.h: add the option of fortified string.h functions

:::::: TO: Daniel Micay <danielmicay@xxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

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