[PATCH AUTOSEL 4.20 043/117] kbuild: let fixdep directly write to .*.cmd files

[PATCH AUTOSEL 4.20 043/117] kbuild: let fixdep directly write to .*.cmd files

[Sasha Levin]

From: Masahiro Yamada <yamada.masahiro@socionext.com>

[ Upstream commit 392885ee82d35d515ba2af7b72c5e357c3002113 ]

Currently, fixdep writes dependencies to .*.tmp, which is renamed to
.*.cmd after everything succeeds. This is a very safe way to avoid
corrupted .*.cmd files. The if_changed_dep has carried this safety
mechanism since it was added in 2002.

If fixdep fails for some reasons or a user terminates the build while
fixdep is running, the incomplete output from the fixdep could be
troublesome.

This is my insight about some bad scenarios:

[1] If the compiler succeeds to generate *.o file, but fixdep fails
    to write necessary dependencies to .*.cmd file, Make will miss
    to rebuild the object when headers or CONFIG options are changed.
    In this case, fixdep should not generate .*.cmd file at all so
    that 'arg-check' will surely trigger the rebuild of the object.

[2] A partially constructed .*.cmd file may not be a syntactically
    correct makefile. The next time Make runs, it would include it,
    then fail to parse it. Once this happens, 'make clean' is be the
    only way to fix it.

In fact, [1] is no longer a problem since commit 9c2af1c7377a ("kbuild:
add .DELETE_ON_ERROR special target"). Make deletes a target file on
any failure in its recipe. Because fixdep is a part of the recipe of
*.o target, if it fails, the *.o is deleted anyway. However, I am a
bit worried about the slight possibility of [2].

So, here is a solution. Let fixdep directly write to a .*.cmd file,
but allow makefiles to include it only when its corresponding target
exists.

This effectively reverts commit 2982c953570b ("kbuild: remove redundant
$(wildcard ...) for cmd_files calculation"), and commit 00d78ab2ba75
("kbuild: remove dead code in cmd_files calculation in top Makefile")
because now we must check the presence of targets.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 Makefile               | 13 +++++++------
 scripts/Kbuild.include | 10 ++++------
 scripts/Makefile.build | 12 +++++-------
 3 files changed, 16 insertions(+), 19 deletions(-)

diff --git a/Makefile b/Makefile
index 7a2a9a175756..28b87f551470 100644
--- a/Makefile
+++ b/Makefile
@@ -1034,6 +1034,8 @@ ifdef CONFIG_GDB_SCRIPTS
 endif
 	+$(call if_changed,link-vmlinux)
 
+targets := vmlinux
+
 # Build samples along the rest of the kernel. This needs headers_install.
 ifdef CONFIG_SAMPLES
 vmlinux-dirs += samples
@@ -1758,13 +1760,12 @@ quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
 cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
                   $(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
 
-# read all saved command lines
-cmd_files := $(wildcard .*.cmd)
+# read saved command lines for existing targets
+existing-targets := $(wildcard $(sort $(targets)))
 
-ifneq ($(cmd_files),)
-  $(cmd_files): ;	# Do not try to update included dependency files
-  include $(cmd_files)
-endif
+cmd_files := $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
+$(cmd_files): ;	# Do not try to update included dependency files
+-include $(cmd_files)
 
 endif   # ifeq ($(config-targets),1)
 endif   # ifeq ($(mixed-targets),1)
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 3d09844405c9..b8c866193ae6 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -262,9 +262,8 @@ ifndef CONFIG_TRIM_UNUSED_KSYMS
 
 cmd_and_fixdep =                                                             \
 	$(echo-cmd) $(cmd_$(1));                                             \
-	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
-	rm -f $(depfile);                                                    \
-	mv -f $(dot-target).tmp $(dot-target).cmd;
+	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
+	rm -f $(depfile);
 
 else
 
@@ -287,9 +286,8 @@ cmd_and_fixdep =                                                             \
 	$(echo-cmd) $(cmd_$(1));                                             \
 	$(ksym_dep_filter) |                                                 \
 		scripts/basic/fixdep -e $(depfile) $@ '$(make-cmd)'          \
-			> $(dot-target).tmp;	                             \
-	rm -f $(depfile);                                                    \
-	mv -f $(dot-target).tmp $(dot-target).cmd;
+			> $(dot-target).cmd;	                             \
+	rm -f $(depfile);
 
 endif
 
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 6a6be9f440cf..1d56f181b917 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -527,18 +527,16 @@ FORCE:
 # optimization, we don't need to read them if the target does not
 # exist, we will rebuild anyway in that case.
 
-cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
+existing-targets := $(wildcard $(sort $(targets)))
 
-ifneq ($(cmd_files),)
-  include $(cmd_files)
-endif
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 
 ifneq ($(KBUILD_SRC),)
 # Create directories for object files if they do not exist
 obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
-# If cmd_files exist, their directories apparently exist.  Skip mkdir.
-exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
-obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
+# If targets exist, their directories apparently exist. Skip mkdir.
+existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
+obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
 ifneq ($(obj-dirs),)
 $(shell mkdir -p $(obj-dirs))
 endif
-- 
2.19.1

[PATCH AUTOSEL 4.20 067/117] kconfig: fix file name and line number of warn_ignored_character()

[Sasha Levin]

From: Masahiro Yamada <yamada.masahiro@socionext.com>

[ Upstream commit 77c1c0fa8b1477c5799bdad65026ea5ff676da44 ]

Currently, warn_ignore_character() displays invalid file name and
line number.

The lexer should use current_file->name and yylineno, while the parser
should use zconf_curname() and zconf_lineno().

This difference comes from that the lexer is always going ahead
of the parser. The parser needs to look ahead one token to make a
shift/reduce decision, so the lexer is requested to scan more text
from the input file.

This commit fixes the warning message from warn_ignored_character().

[Test Code]

  ----(Kconfig begin)----
  /
  -----(Kconfig end)-----

[Output]

  Before the fix:

  <none>:0:warning: ignoring unsupported character '/'

  After the fix:

  Kconfig:1:warning: ignoring unsupported character '/'

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 scripts/kconfig/zconf.l | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index 25bd2b89fe3f..eeac64ccc730 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -73,7 +73,7 @@ static void warn_ignored_character(char chr)
 {
 	fprintf(stderr,
 	        "%s:%d:warning: ignoring unsupported character '%c'\n",
-	        zconf_curname(), zconf_lineno(), chr);
+	        current_file->name, yylineno, chr);
 }
 %}
 
-- 
2.19.1

[PATCH AUTOSEL 4.20 068/117] kconfig: fix memory leak when EOF is encountered in quotation

[Sasha Levin]

From: Masahiro Yamada <yamada.masahiro@socionext.com>

[ Upstream commit fbac5977d81cb2b2b7e37b11c459055d9585273c ]

An unterminated string literal followed by new line is passed to the
parser (with "multi-line strings not supported" warning shown), then
handled properly there.

On the other hand, an unterminated string literal at end of file is
never passed to the parser, then results in memory leak.

[Test Code]

  ----------(Kconfig begin)----------
  source "Kconfig.inc"

  config A
          bool "a"
  -----------(Kconfig end)-----------

  --------(Kconfig.inc begin)--------
  config B
          bool "b\No new line at end of file
  ---------(Kconfig.inc end)---------

[Summary from Valgrind]

  Before the fix:

    LEAK SUMMARY:
       definitely lost: 16 bytes in 1 blocks
       ...

  After the fix:

    LEAK SUMMARY:
       definitely lost: 0 bytes in 0 blocks
       ...

Eliminate the memory leak path by handling this case. Of course, such
a Kconfig file is wrong already, so I will add an error message later.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 scripts/kconfig/zconf.l | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index eeac64ccc730..c2f577d71964 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -221,6 +221,8 @@ n	[A-Za-z0-9_-]
 	}
 	<<EOF>>	{
 		BEGIN(INITIAL);
+		yylval.string = text;
+		return T_WORD_QUOTE;
 	}
 }
 
-- 
2.19.1