If CONFIG_BUG is not defined, then macro __WARN is not defined. This shows as the following build error: CC [M] drivers/media/v4l2-core/videobuf2-core.o drivers/media/v4l2-core/videobuf2-core.c: In function ‘vb2_warn_zero_bytesused’: drivers/media/v4l2-core/videobuf2-core.c:1253:2: error: implicit declaration of function ‘__WARN’ [-Werror=implicit-function-declaration] __WARN(); ^ This problem has been bisected to commit 77a3c6fd90c94f635edb00d4a65f485687538791. Signed-off-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx> Cc: linux-arch@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx --- V2 - Fix infinite loop for __WARN as noted by Joe Perches --- include/asm-generic/bug.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 630dd23..c1cb4b3 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -137,6 +137,7 @@ extern void warn_slowpath_null(const char *file, const int line); }) #else /* !CONFIG_BUG */ +#define __WARN() do {} while (0) #ifndef HAVE_ARCH_BUG #define BUG() do {} while (1) #endif -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html