Hi, all!

This is the result of testing randconfig with KCONFIG_SEED=0xEE7AB52F in next-20240703 vanilla tree on
Ubuntu 22.04 LTS. GCC used is gcc (Ubuntu 12.3.0-1ubuntu1~22.04) 12.3.0.

The particular error is as follows:

In file included from ./include/linux/string.h:374,
                 from ./arch/x86/include/asm/page_32.h:18,
                 from ./arch/x86/include/asm/page.h:14,
                 from ./arch/x86/include/asm/processor.h:20,
                 from ./include/linux/sched.h:13,
                 from ./include/linux/audit.h:12,
                 from kernel/seccomp.c:19:
In function ‘fortify_memcpy_chk’,
    inlined from ‘syscall_get_arguments’ at ./arch/x86/include/asm/syscall.h:85:2,
    inlined from ‘populate_seccomp_data’ at kernel/seccomp.c:258:2,
    inlined from ‘__seccomp_filter’ at kernel/seccomp.c:1231:3:
./include/linux/fortify-string.h:580:25: error: call to ‘__read_overflow2_field’ declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struc
t_group()? [-Werror=attribute-warning]
  580 |                         __read_overflow2_field(q_size_field, size);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



The offending code is here (introduced by commit f68f2ff91512c):

  547 __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
  548                                          const size_t p_size,
  549                                          const size_t q_size,
  550                                          const size_t p_size_field,
  551                                          const size_t q_size_field,
  552                                          const u8 func)
  553 {
  554         if (__builtin_constant_p(size)) {
  555                 /*
  556                  * Length argument is a constant expression, so we
  557                  * can perform compile-time bounds checking where
  558                  * buffer sizes are also known at compile time.
  559                  */
  560 
  561                 /* Error when size is larger than enclosing struct. */
  562                 if (__compiletime_lessthan(p_size_field, p_size) &&
  563                     __compiletime_lessthan(p_size, size))
  564                         __write_overflow();
  565                 if (__compiletime_lessthan(q_size_field, q_size) &&
  566                     __compiletime_lessthan(q_size, size))
  567                         __read_overflow2();
  568 
  569                 /* Warn when write size argument larger than dest field. */
  570                 if (__compiletime_lessthan(p_size_field, size))
  571                         __write_overflow_field(p_size_field, size);
  572                 /*
  573                  * Warn for source field over-read when building with W=1
  574                  * or when an over-write happened, so both can be fixed at
  575                  * the same time.
  576                  */
  577                 if ((IS_ENABLED(KBUILD_EXTRA_WARN1) ||
  578                      __compiletime_lessthan(p_size_field, size)) &&
  579                     __compiletime_lessthan(q_size_field, size))
→ 580                         __read_overflow2_field(q_size_field, size);
  581         }

I have no idea why GCC 12.3.0 complained here, even less how to fix it.

This is the inherent problem with reporting warnings and errors from a "randconfig" .config -
one gets errors in completely unfamiliar parts of 35 millions lines :-P

Hope this helps.

Best regards,
Mirsad Todorovac