• Arnd Bergmann's avatar
    ubsan: build ubsan.c more conservatively · af700eae
    Arnd Bergmann authored
    objtool points out several conditions that it does not like, depending
    on the combination with other configuration options and compiler
    variants:
    
    stack protector:
      lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0xbf: call to __stack_chk_fail() with UACCESS enabled
      lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0xbe: call to __stack_chk_fail() with UACCESS enabled
    
    stackleak plugin:
      lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x4a: call to stackleak_track_stack() with UACCESS enabled
      lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x4a: call to stackleak_track_stack() with UACCESS enabled
    
    kasan:
      lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x25: call to memcpy() with UACCESS enabled
      lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x25: call to memcpy() with UACCESS enabled
    
    The stackleak and kasan options just need to be disabled for this file
    as we do for other files already.  For the stack protector, we already
    attempt to disable it, but this fails on clang because the check is
    mixed with the gcc specific -fno-conserve-stack option.  According to
    Andrey Ryabinin, that option is not even needed, dropping it here fixes
    the stackprotector issue.
    
    Link: http://lkml.kernel.org/r/20190722125139.1335385-1-arnd@arndb.de
    Link: https://lore.kernel.org/lkml/20190617123109.667090-1-arnd@arndb.de/t/
    Link: https://lore.kernel.org/lkml/20190722091050.2188664-1-arnd@arndb.de/t/
    Fixes: d08965a2 ("x86/uaccess, ubsan: Fix UBSAN vs. SMAP")
    Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    Reviewed-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Matthew Wilcox <willy@infradead.org>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    af700eae
Makefile 9.47 KB