+ selftests-vm-fix-incorrect-gcc-invocation-in-some-cases.patch added to -mm tree

+ selftests-vm-fix-incorrect-gcc-invocation-in-some-cases.patch added to -mm tree

[akpm]

The patch titled
     Subject: selftests/vm: fix incorrect gcc invocation in some cases
has been added to the -mm tree.  Its filename is
     selftests-vm-fix-incorrect-gcc-invocation-in-some-cases.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/selftests-vm-fix-incorrect-gcc-invocation-in-some-cases.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/selftests-vm-fix-incorrect-gcc-invocation-in-some-cases.patch

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------------------------------------------------------
From: John Hubbard <jhubbard@nvidia.com>
Subject: selftests/vm: fix incorrect gcc invocation in some cases

Avoid accidental wrong builds, due to built-in rules working just a little
bit too well--but not quite as well as required for our situation here.

In other words, "make userfaultfd" (for example) is supposed to fail to
build at all, because this Makefile only supports either "make" (all), or
"make /full/path".  However, the built-in rules, if not suppressed, will
pick up CFLAGS and the initial LDLIBS (but not the target-specific LDLIBS,
because those are only set for the full path target!).  This causes it to
get pretty far into building things despite using incorrect values such as
an *occasionally* incomplete LDLIBS value.

Link: https://lkml.kernel.org/r/20200915012901.1655280-3-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/vm/Makefile |   12 ++++++++++++
 1 file changed, 12 insertions(+)

--- a/tools/testing/selftests/vm/Makefile~selftests-vm-fix-incorrect-gcc-invocation-in-some-cases
+++ a/tools/testing/selftests/vm/Makefile
@@ -8,6 +8,18 @@ MACHINE ?= $(shell echo $(uname_M) | sed
 # make invocations:
 .DELETE_ON_ERROR:
 
+# Avoid accidental wrong builds, due to built-in rules working just a little
+# bit too well--but not quite as well as required for our situation here.
+#
+# In other words, "make userfaultfd" is supposed to fail to build at all,
+# because this Makefile only supports either "make" (all), or "make /full/path".
+# However,  the built-in rules, if not suppressed, will pick up CFLAGS and the
+# initial LDLIBS (but not the target-specific LDLIBS, because those are only
+# set for the full path target!). This causes it to get pretty far into building
+# things despite using incorrect values such as an *occasionally* incomplete
+# LDLIBS.
+MAKEFLAGS += --no-builtin-rules
+
 CFLAGS = -Wall -I ../../../../usr/include $(EXTRA_CFLAGS)
 LDLIBS = -lrt
 TEST_GEN_FILES = compaction_test
_

Patches currently in -mm which might be from jhubbard@nvidia.com are

mm-dump_page-rename-head_mapcount-head_compound_mapcount.patch
selftests-vm-fix-false-build-success-on-the-second-and-later-attempts.patch
selftests-vm-fix-incorrect-gcc-invocation-in-some-cases.patch