On Sun, 11 Oct 2020 11:24:07 +0200 Oliver Hartkopp wrote: > diff --git a/net/can/isotp.c b/net/can/isotp.c > index e6ff032b5426..22187669c5c9 100644 > --- a/net/can/isotp.c > +++ b/net/can/isotp.c > @@ -79,6 +79,8 @@ MODULE_LICENSE("Dual BSD/GPL"); > MODULE_AUTHOR("Oliver Hartkopp <socketcan@xxxxxxxxxxxx>"); > MODULE_ALIAS("can-proto-6"); > > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt You need to move this before the includes: net/can/isotp.c:82: warning: "pr_fmt" redefined 82 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | In file included from ../include/linux/kernel.h:15, from ../include/linux/list.h:9, from ../include/linux/module.h:12, from ../net/can/isotp.c:56: include/linux/printk.h:297: note: this is the location of the previous definition 297 | #define pr_fmt(fmt) fmt | net/can/isotp.c:82:9: warning: preprocessor token pr_fmt redefined net/can/isotp.c: note: in included file (through ../include/linux/kernel.h, ../include/linux/list.h, ../include/linux/module.h): include/linux/printk.h:297:9: this was the original definition