On Mon, 24 Aug 2020 10:59:13 +0800
Nicolas Boichat <drinkcat@xxxxxxxxxxxx> wrote:
> ---
>
> Changes since v4:
> - Turns this into a make option, instead of a config
> option, as suggested by Steven Rostedt <rostedt@xxxxxxxxxxx>.
>
> Changes since v2/v3:
> - Rebase only, v3 didn't exist as I just split out the other
> necessary patches.
> - Added patch 3/3 to fix atomisp_compat_css20.c
>
> Changes since v1:
> - Use static_assert instead of __static_assert (Jason Gunthorpe)
> - Fix issues that can be detected by this patch (running some
> randconfig in a loop, kernel test robot, or manual inspection),
> by:
> - Making some debug config options that use trace_printk depend
> on the new config option.
> - Adding 3 patches before this one.
>
> Makefile | 14 ++++++++++++++
> include/linux/kernel.h | 17 ++++++++++++++++-
> 2 files changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index c4470a4e131f2ce..fb8b0d7fb4b2df7 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -100,6 +100,16 @@ endif
>
> export quiet Q KBUILD_VERBOSE
>
> +# Disallow use of trace_printk. Can be used by production kernels.
> +ifeq ("$(origin DISALLOW_TRACE_PRINTK)", "command line")
> + KBUILD_DISALLOW_TRACE_PRINTK = $(DISALLOW_TRACE_PRINTK)
> +endif
> +ifndef KBUILD_DISALLOW_TRACE_PRINTK
> + KBUILD_DISALLOW_TRACE_PRINTK = 0
> +endif
> +
> +export KBUILD_DISALLOW_TRACE_PRINTK
> +
> # Kbuild will save output files in the current working directory.
> # This does not need to match to the root of the kernel source tree.
> #
> @@ -838,6 +848,10 @@ KBUILD_AFLAGS += -gz=zlib
> KBUILD_LDFLAGS += --compress-debug-sections=zlib
> endif
>
> +ifeq ($(KBUILD_DISALLOW_TRACE_PRINTK),1)
> +KBUILD_CFLAGS += -DDISALLOW_TRACE_PRINTK
> +endif
> +
> KBUILD_CFLAGS += $(DEBUG_CFLAGS)
> export DEBUG_CFLAGS
>
There's one more thing we need to do, is if you build without this option
then build with it, you should trigger a full kernel rebuild.
Otherwise, if you build without the option, then build with it, and it
doesn't rebuild the tree, it wont catch anything.
-- Steve
