diff options
authorMasahiro Yamada <>2019-07-12 15:07:09 +0900
committerMasahiro Yamada <>2019-07-17 22:37:51 +0900
commit8e2442a5f86e1f77b86401fce274a7f622740bc4 (patch)
parent5a46421789f46165416d2b4834647b153c231c55 (diff)
kconfig: fix missing choice values in auto.conf
Since commit 00c864f8903d ("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 beaaddb62540 ("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 5d09598d488f ("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: 00c864f8903d ("kconfig: allow all config targets to write auto.conf if missing") Cc: linux-stable <> # 4.19+ Reported-by: Joonas Kylmälä <> Signed-off-by: Masahiro Yamada <> Tested-by: Joonas Kylmälä <>
2 files changed, 4 insertions, 4 deletions
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 501fdcc5e999..1134892599da 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -895,7 +895,8 @@ int conf_write(const char *name)
"# %s\n"
"#\n", str);
need_newline = false;
- } else if (!(sym->flags & SYMBOL_CHOICE)) {
+ } else if (!(sym->flags & SYMBOL_CHOICE) &&
+ !(sym->flags & SYMBOL_WRITTEN)) {
if (!(sym->flags & SYMBOL_WRITE))
goto next;
@@ -903,7 +904,7 @@ int conf_write(const char *name)
fprintf(out, "\n");
need_newline = false;
- sym->flags &= ~SYMBOL_WRITE;
+ sym->flags |= SYMBOL_WRITTEN;
conf_write_symbol(out, sym, &kconfig_printer_cb, NULL);
@@ -1063,8 +1064,6 @@ int conf_write_autoconf(int overwrite)
if (!overwrite && is_present(autoconf_name))
return 0;
- sym_clear_all_valid();
if (conf_touch_deps())
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index 8dde65bc3165..017843c9a4f4 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -141,6 +141,7 @@ struct symbol {
#define SYMBOL_OPTIONAL 0x0100 /* choice is optional - values can be 'n' */
#define SYMBOL_WRITE 0x0200 /* write symbol to file (KCONFIG_CONFIG) */
#define SYMBOL_CHANGED 0x0400 /* ? */
+#define SYMBOL_WRITTEN 0x0800 /* track info to avoid double-write to .config */
#define SYMBOL_NO_WRITE 0x1000 /* Symbol for internal use only; it will not be written */
#define SYMBOL_CHECKED 0x2000 /* used during dependency checking */
#define SYMBOL_WARNED 0x8000 /* warning has been issued */