[Error after setting -Og] â__bad_copy_fromâ declared with attribute error: copy source size is too small

[Wei Wei]

Hi all,

I get a compile time error after setting -Og when compiling for the latest GitHub version.
I am using `make defconfigâ to get the default x86_64 config. But previously I did this in v4.4, 
it's fine.

Modification to Makefile:
KBUILD_CFLAGS  += -O2 $(call cc-disable-warning,maybe-uninitialized,)            
       else                                                                  
       -KBUILD_CFLAGS   += -O2                                                    
       +KBUILD_CFLAGS   += -Og                                                    
       endif                                                                    
       endif   

And error info:
In file included from ./arch/x86/include/asm/preempt.h:6:0,                        
  from ./include/linux/preempt.h:80,                                              
  from ./include/linux/rcupdate.h:40,                                             
  from ./include/linux/rculist.h:10,                                              
  from ./include/linux/pid.h:4,                                                   
  from ./include/linux/sched.h:13,                                                
  from kernel/ptrace.c:12:                                                        
  In function âcheck_copy_sizeâ,                                                  
  inlined from âcopy_to_userâ at ./include/linux/uaccess.h:153:6,                 
  inlined from âptrace_requestâ at kernel/ptrace.c:934:7:                         
  ./include/linux/thread_info.h:138:4: error: call to â__bad_copy_fromâ declared 
with attribute error: copy source size is too small
  __bad_copy_from();                                                              
  ^                                                                               
  scripts/Makefile.build:313: recipe for target 'kernel/ptrace.o' failed          
  make[1]: *** [kernel/ptrace.o] Error 1                                          
  Makefile:1023: recipe for target âkernel' failed  

Any help is appreciated!

Thank you,
Wei