linux/scripts/kconfig
Masahiro Yamada 8e2442a5f8 kconfig: fix missing choice values in auto.conf
Since commit 00c864f890 ("kconfig: allow all config targets to write
auto.conf if missing"), Kconfig creates include/config/auto.conf in the
defconfig stage when it is missing.

Joonas Kylmälä reported incorrect auto.conf generation under some
circumstances.

To reproduce it, apply the following diff:

|  --- a/arch/arm/configs/imx_v6_v7_defconfig
|  +++ b/arch/arm/configs/imx_v6_v7_defconfig
|  @@ -345,14 +345,7 @@ CONFIG_USB_CONFIGFS_F_MIDI=y
|   CONFIG_USB_CONFIGFS_F_HID=y
|   CONFIG_USB_CONFIGFS_F_UVC=y
|   CONFIG_USB_CONFIGFS_F_PRINTER=y
|  -CONFIG_USB_ZERO=m
|  -CONFIG_USB_AUDIO=m
|  -CONFIG_USB_ETH=m
|  -CONFIG_USB_G_NCM=m
|  -CONFIG_USB_GADGETFS=m
|  -CONFIG_USB_FUNCTIONFS=m
|  -CONFIG_USB_MASS_STORAGE=m
|  -CONFIG_USB_G_SERIAL=m
|  +CONFIG_USB_FUNCTIONFS=y
|   CONFIG_MMC=y
|   CONFIG_MMC_SDHCI=y
|   CONFIG_MMC_SDHCI_PLTFM=y

And then, run:

$ make ARCH=arm mrproper imx_v6_v7_defconfig

You will see CONFIG_USB_FUNCTIONFS=y is correctly contained in the
.config, but not in the auto.conf.

Please note drivers/usb/gadget/legacy/Kconfig is included from a choice
block in drivers/usb/gadget/Kconfig. So USB_FUNCTIONFS is a choice value.

This is probably a similar situation described in commit beaaddb625
("kconfig: tests: test defconfig when two choices interact").

When sym_calc_choice() is called, the choice symbol forgets the
SYMBOL_DEF_USER unless all of its choice values are explicitly set by
the user.

The choice symbol is given just one chance to recall it because
set_all_choice_values() is called if SYMBOL_NEED_SET_CHOICE_VALUES
is set.

When sym_calc_choice() is called again, the choice symbol forgets it
forever, since SYMBOL_NEED_SET_CHOICE_VALUES is a one-time aid.
Hence, we cannot call sym_clear_all_valid() again and again.

It is crazy to repeat set and unset of internal flags. However, we
cannot simply get rid of "sym->flags &= flags | ~SYMBOL_DEF_USER;"
Doing so would re-introduce the problem solved by commit 5d09598d48
("kconfig: fix new choices being skipped upon config update").

To work around the issue, conf_write_autoconf() stopped calling
sym_clear_all_valid().

conf_write() must be changed accordingly. Currently, it clears
SYMBOL_WRITE after the symbol is written into the .config file. This
is needed to prevent it from writing the same symbol multiple times in
case the symbol is declared in two or more locations. I added the new
flag SYMBOL_WRITTEN, to track the symbols that have been written.

Anyway, this is a cheesy workaround in order to suppress the issue
as far as defconfig is concerned.

Handling of choices is totally broken. sym_clear_all_valid() is called
every time a user touches a symbol from the GUI interface. To reproduce
it, just add a new symbol drivers/usb/gadget/legacy/Kconfig, then touch
around unrelated symbols from menuconfig. USB_FUNCTIONFS will disappear
from the .config file.

I added the Fixes tag since it is more fatal than before. But, this
has been broken since long long time before, and still it is.
We should take a closer look to fix this correctly somehow.

Fixes: 00c864f890 ("kconfig: allow all config targets to write auto.conf if missing")
Cc: linux-stable <stable@vger.kernel.org> # 4.19+
Reported-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
2019-07-17 22:37:51 +09:00
..
lxdialog kconfig: remove trailing whitespaces 2019-05-09 22:37:17 +09:00
tests docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
.gitignore kconfig: rename generated .*conf-cfg to *conf-cfg 2019-01-06 10:47:09 +09:00
conf.c kconfig: Fix spelling of sym_is_changable 2019-07-06 21:58:23 +09:00
confdata.c kconfig: fix missing choice values in auto.conf 2019-07-17 22:37:51 +09:00
expr.c kconfig: split some C files out of zconf.y 2018-12-28 22:22:38 +09:00
expr.h kconfig: fix missing choice values in auto.conf 2019-07-17 22:37:51 +09:00
gconf-cfg.sh kconfig: do not require pkg-config on make {menu,n}config 2018-09-03 02:13:48 +09:00
gconf.c kconfig: remove trailing whitespaces 2019-05-09 22:37:17 +09:00
gconf.glade scripts/kconfig/gconf.glade Update broken web addresses. 2010-09-17 16:54:42 +02:00
images.c kconfig: split images.c out of qconf.cc/gconf.c to fix gconf warnings 2018-12-28 22:22:39 +09:00
images.h kconfig: split images.c out of qconf.cc/gconf.c to fix gconf warnings 2018-12-28 22:22:39 +09:00
lexer.l kconfig: use snprintf for formatting pathnames 2019-05-14 23:23:25 +09:00
list.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lkc_proto.h kconfig: Fix spelling of sym_is_changable 2019-07-06 21:58:23 +09:00
lkc.h kconfig: require the argument of --defconfig 2019-06-09 15:08:18 +09:00
Makefile kconfig: run olddefconfig instead of oldconfig after merging fragments 2019-07-17 10:25:10 +09:00
mconf-cfg.sh kconfig: do not require pkg-config on make {menu,n}config 2018-09-03 02:13:48 +09:00
mconf.c kconfig: Fix spelling of sym_is_changable 2019-07-06 21:58:23 +09:00
menu.c kconfig: convert to SPDX License Identifier 2018-12-28 22:22:28 +09:00
merge_config.sh kconfig: convert to SPDX License Identifier 2018-12-28 22:22:28 +09:00
nconf-cfg.sh kconfig: Make nconf-cfg.sh executable 2019-04-09 22:44:57 +09:00
nconf.c kconfig: Fix spelling of sym_is_changable 2019-07-06 21:58:23 +09:00
nconf.gui.c kconfig/[mn]conf: handle backspace (^H) key 2019-03-29 22:48:01 +09:00
nconf.h kconfig: convert to SPDX License Identifier 2018-12-28 22:22:28 +09:00
parser.y kconfig: rename zconf.y to parser.y 2019-02-13 23:25:58 +09:00
preprocess.c kconfig: add static qualifier to expand_string() 2019-06-09 15:08:18 +09:00
qconf-cfg.sh kconfig: do not require pkg-config on make {menu,n}config 2018-09-03 02:13:48 +09:00
qconf.cc kconfig: Fix spelling of sym_is_changable 2019-07-06 21:58:23 +09:00
qconf.h kconfig: fix 'Save As' menu of xconfig 2019-03-12 02:50:24 +09:00
streamline_config.pl kconfig: convert to SPDX License Identifier 2018-12-28 22:22:28 +09:00
symbol.c Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
util.c kconfig: convert to SPDX License Identifier 2018-12-28 22:22:28 +09:00