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

[Vipin Sharma <vipinsh@google.com>]

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

> > >
> > > 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.

> > > > +# --- 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/

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.