On Wed, Dec 09, 2020 at 11:01:52AM +0100, Dmitry Vyukov wrote: > Both KCOV and UBSAN use compiler instrumentation. If UBSAN detects a bug > in KCOV, it may cause infinite recursion via printk and other common > functions. We already don't instrument KCOV with KASAN/KCSAN for this > reason, don't instrument it with UBSAN as well. > > As a side effect this also resolves the following gcc warning: > > conflicting types for built-in function '__sanitizer_cov_trace_switch'; > expected 'void(long unsigned int, void *)' [-Wbuiltin-declaration-mismatch] > > It's only reported when kcov.c is compiled with any of the sanitizers > enabled. Size of the arguments is correct, it's just that gcc uses 'long' > on 64-bit arches and 'long long' on 32-bit arches, while kernel type is > always 'long long'. > > Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > Suggested-by: Marco Elver <elver@xxxxxxxxxx> > Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Thanks for chasing this down! Andrew, can you add this to the stack of ubsan patches you're carrying, please? -- Kees Cook
