scripts/Makefile.extrawarn: Do not show clang's non-kprintf warnings at W=1

[ Upstream commit 738fc998b639407346a9e026514f0562301462cd ]

Clang's -Wformat-overflow and -Wformat-truncation have chosen to check
'%p' unlike GCC but it does not know about the kernel's pointer
extensions in lib/vsprintf.c, so the developers split that part of the
warning out for the kernel to disable because there will always be false
positives.

Commit 908dd508 ("kbuild: enable -Wformat-truncation on clang") did
disabled these warnings but only in a block that would be called when
W=1 was not passed, so they would appear with W=1. Move the disabling of
the non-kprintf warnings to a block that always runs so that they are
never seen, regardless of warning level.

Fixes: 908dd508 ("kbuild: enable -Wformat-truncation on clang")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501291646.VtwF98qd-lkp@intel.com/


Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

scripts/Makefile.extrawarn

@@ -31,6 +31,11 @@ KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
 ifdef CONFIG_CC_IS_CLANG
 # The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable.
 KBUILD_CFLAGS += -Wno-gnu
+
+# Clang checks for overflow/truncation with '%p', while GCC does not:
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219
+KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow-non-kprintf)
+KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation-non-kprintf)
 else
 
 # gcc inanely warns about local variables called 'main'
@@ -102,11 +107,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow)
 ifdef CONFIG_CC_IS_GCC
 KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation)
-else
-# Clang checks for overflow/truncation with '%p', while GCC does not:
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219
-KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow-non-kprintf)
-KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation-non-kprintf)
 endif
 KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)