linux-kernel - Re: [PATCH v4 26/30] selftests/liveupdate: Add multi-kexec session lifecycle test

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Message-ID: <20251003225120.GA2035091.vipinsh@google.com>
Date: Fri, 3 Oct 2025 15:51:20 -0700
From: Vipin Sharma <vipinsh@...gle.com>
To: Pasha Tatashin <pasha.tatashin@...een.com>
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Subject: Re: [PATCH v4 26/30] selftests/liveupdate: Add multi-kexec session
 lifecycle test

On 2025-09-29 01:03:17, Pasha Tatashin wrote:
> diff --git a/tools/testing/selftests/liveupdate/.gitignore b/tools/testing/selftests/liveupdate/.gitignore
> index af6e773cf98f..de7ca45d3892 100644
> --- a/tools/testing/selftests/liveupdate/.gitignore
> +++ b/tools/testing/selftests/liveupdate/.gitignore
> @@ -1 +1,2 @@
>  /liveupdate
> +/luo_multi_kexec

In next patches new tests are not added to gitignore.

> diff --git a/tools/testing/selftests/liveupdate/Makefile b/tools/testing/selftests/liveupdate/Makefile
> index 2a573c36016e..1cbc816ed5c5 100644
> --- a/tools/testing/selftests/liveupdate/Makefile
> +++ b/tools/testing/selftests/liveupdate/Makefile
> @@ -1,7 +1,38 @@
>  # SPDX-License-Identifier: GPL-2.0-only
> +
> +KHDR_INCLUDES ?= -I../../../usr/include

If make is run from the tools/testing/selftests/liveupdate directory, this
will not work because it needs one more "..".

If this is built using selftest Makefile from root directory

  make -C tools/testing/selftests TARGETS=liveupdate

there will not be build errors because tools/testing/selftests/Makefile
defines KHDR_INCLUDES, so above definition will never happen.

>  CFLAGS += -Wall -O2 -Wno-unused-function
>  CFLAGS += $(KHDR_INCLUDES)
> +LDFLAGS += -static

Why static? Can't we let user pass extra flags if they prefer static

> +
> +# --- Test Configuration (Edit this section when adding new tests) ---
> +LUO_SHARED_SRCS := luo_test_utils.c
> +LUO_SHARED_HDRS += luo_test_utils.h
> +
> +LUO_MANUAL_TESTS += luo_multi_kexec
> +
> +TEST_FILES += do_kexec.sh
>  
>  TEST_GEN_PROGS += liveupdate
>  
> +# --- Automatic Rule Generation (Do not edit below) ---
> +
> +TEST_GEN_PROGS_EXTENDED += $(LUO_MANUAL_TESTS)
> +
> +# Define the full list of sources for each manual test.
> +$(foreach test,$(LUO_MANUAL_TESTS), \
> +	$(eval $(test)_SOURCES := $(test).c $(LUO_SHARED_SRCS)))
> +
> +# This loop automatically generates an explicit build rule for each manual test.
> +# It includes dependencies on the shared headers and makes the output
> +# executable.
> +# Note the use of '$$' to escape automatic variables for the 'eval' command.
> +$(foreach test,$(LUO_MANUAL_TESTS), \
> +	$(eval $(OUTPUT)/$(test): $($(test)_SOURCES) $(LUO_SHARED_HDRS) \
> +		$(call msg,LINK,,$$@) ; \
> +		$(Q)$(LINK.c) $$^ $(LDLIBS) -o $$@ ; \
> +		$(Q)chmod +x $$@ \
> +	) \
> +)
> +
>  include ../lib.mk

make is not building LUO_MANUAL_TESTS, it is only building liveupdate.
How to build them?

I ended up making bunch of changes in the Makefile to fix these issues.
Following is the diff (it is based on last patch of the series). It
allows in-tree build, out-of-tree build, and build other tests as well.

diff --git a/tools/testing/selftests/liveupdate/Makefile b/tools/testing/selftests/liveupdate/Makefile
index 25a6dec790bb..fbcacbd1b798 100644
--- a/tools/testing/selftests/liveupdate/Makefile
+++ b/tools/testing/selftests/liveupdate/Makefile
@@ -1,10 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-KHDR_INCLUDES ?= -I../../../usr/include
-CFLAGS += -Wall -O2 -Wno-unused-function
-CFLAGS += $(KHDR_INCLUDES)
-LDFLAGS += -static
-
 # --- Test Configuration (Edit this section when adding new tests) ---
 LUO_SHARED_SRCS := luo_test_utils.c
 LUO_SHARED_HDRS += luo_test_utils.h
@@ -25,6 +20,12 @@ TEST_GEN_PROGS := $(LUO_MAIN_TESTS)
 
 liveupdate_SOURCES := liveupdate.c $(LUO_SHARED_SRCS)
 
+include ../lib.mk
+
+CFLAGS += -Wall -O2 -Wno-unused-function
+CFLAGS += $(KHDR_INCLUDES)
+LDFLAGS += -static
+
 $(OUTPUT)/liveupdate: $(liveupdate_SOURCES) $(LUO_SHARED_HDRS)
        $(call msg,LINK,,$@)
        $(Q)$(LINK.c) $^ $(LDLIBS) -o $@
@@ -33,16 +34,16 @@ $(OUTPUT)/liveupdate: $(liveupdate_SOURCES) $(LUO_SHARED_HDRS)
 $(foreach test,$(LUO_MANUAL_TESTS), \
        $(eval $(test)_SOURCES := $(test).c $(LUO_SHARED_SRCS)))
 
+define BUILD_RULE_TEMPLATE
+$(OUTPUT)/$(1): $($(1)_SOURCES) $(LUO_SHARED_HDRS)
+       $(call msg,LINK,,$$@)
+       $(Q)$(LINK.c) $$^ $(LDLIBS) -o $$@
+       $(Q)chmod +x $$@
+endef
 # This loop automatically generates an explicit build rule for each manual test.
 # It includes dependencies on the shared headers and makes the output
 # executable.
 # Note the use of '$$' to escape automatic variables for the 'eval' command.
 $(foreach test,$(LUO_MANUAL_TESTS), \
-       $(eval $(OUTPUT)/$(test): $($(test)_SOURCES) $(LUO_SHARED_HDRS) \
-               $(call msg,LINK,,$$@) ; \
-               $(Q)$(LINK.c) $$^ $(LDLIBS) -o $$@ ; \
-               $(Q)chmod +x $$@ \
-       ) \
+       $(eval $(call BUILD_RULE_TEMPLATE,$(test))) \
 )
-
-include ../lib.mk