BUG() does not return, and arch implementations of BUG() use unreachable() or other non-returning code. However with !CONFIG_BUG, the default implementation is often used instead, and that does not do that. x86 always uses its own implementation, but powerpc with !CONFIG_BUG gives a build error: kernel/time/timekeeping.c: In function ‘timekeeping_debug_get_ns’: kernel/time/timekeeping.c:286:1: error: no return statement in function returning non-void [-Werror=return-type] Add unreachable() to default !CONFIG_BUG BUG() implementation. Fixes: e8e9d21a5df6 ("timekeeping: Refactor timekeeping helpers") Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> Closes: https://lore.kernel.org/all/CA+G9fYvjdZCW=7ZGxS6A_3bysjQ56YF7S-+PNLQ_8a4DKh1Bhg@xxxxxxxxxxxxxx/ Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> --- include/asm-generic/bug.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 6e794420bd39..b7de3a4eade1 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -156,7 +156,10 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...); #else /* !CONFIG_BUG */ #ifndef HAVE_ARCH_BUG -#define BUG() do {} while (1) +#define BUG() do { \ + do {} while (1); \ + unreachable(); \ +} while (0) #endif #ifndef HAVE_ARCH_BUG_ON -- 2.34.1