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

On 2025-10-03 22:37:10, Pasha Tatashin wrote:

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--- 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 "..".

This causes a build issue, see my response at the bottom.

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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.

If one is just building test using the above make command (without
install) we don't see other liveupdate test binaries.

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+# --- 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 am building them out of tree:
make O=x86_64 -s -C tools/testing/selftests TARGETS=liveupdate install
make O=x86_64 -s -C tools/testing/selftests TARGETS=kho install

Actually, I just tested in-tree and everything works for me, could you
please verify:

make mrproper  # Clean the tree
cat tools/testing/selftests/liveupdate/config > .config # Copy LUO depends.
make olddefconfig  # make a def config with LUO
make kvm_guest.config # Build minimal KVM guest with LUO
make headers # Make uAPI headers
make -C tools/testing/selftests TARGETS=liveupdate install # make and
install liveupdate selftests

Yes, this one builds the tests.

However, if instead of using the above make command, we do

  cd tools/testing/selftests/liveupdate
  make

This will error out

    LINK     liveupdate
  liveupdate.c:19:10: fatal error: linux/liveupdate.h: No such file or directory
     19 | #include <linux/liveupdate.h>
        |          ^~~~~~~~~~~~~~~~~~~~
  compilation terminated.
  In file included from luo_test_utils.c:21:
  luo_test_utils.h:13:10: fatal error: linux/liveupdate.h: No such file or directory
     13 | #include <linux/liveupdate.h>
        |          ^~~~~~~~~~~~~~~~~~~~
  compilation terminated.
  In file included from <command-line>:
  /usr/include/stdc-predef.h:1: fatal error: cannot create precompiled header /liveupdate: Permission denied
      1 | /* Copyright (C) 1991-2025 Free Software Foundation, Inc.
  compilation terminated.
  make: *** [Makefile:30: /liveupdate] Error 1

Reason for this build error is KHDR_INCLUDES in the selftest/liveupdate/Makefile

Following fix resolves this above two "No such file or directory" error.

diff --git a/tools/testing/selftests/liveupdate/Makefile b/tools/testing/selftests/liveupdate/Makefile
index 25a6dec790bb..6507682addac 100644
--- a/tools/testing/selftests/liveupdate/Makefile
+++ b/tools/testing/selftests/liveupdate/Makefile

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only

-KHDR_INCLUDES ?= -I../../../usr/include
+KHDR_INCLUDES ?= -I../../../../usr/include
 CFLAGS += -Wall -O2 -Wno-unused-function
 CFLAGS += $(KHDR_INCLUDES)
 LDFLAGS += -static

My git diff in the first response fixes build issue and generate tests.
https://lore.kernel.org/linux-mm/20251003225120.GA2035091.vipinsh@google.com/ (local)

I am used to kvm and vfio selftests. They both build all their binaries
by running 'make' from their directories. That's why I found it odd that
liveupdate is behaving differently.