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Commit 746bb4ed authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'vla-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux 

Pull VLA removal from Kees Cook:
 "Globally warn on VLA use.

  This turns on "-Wvla" globally now that the last few trees with their
  VLA removals have landed (crypto, block, net, and powerpc).

  Arnd mentioned that there may be a couple more VLAs hiding in
  hard-to-find randconfigs, but nothing big has shaken out in the last
  month or so in linux-next.

  We should be basically VLA-free now! Wheee. :)

  Summary:

   - Remove unused fallback for BUILD_BUG_ON (which technically contains
     a VLA)

   - Lift -Wvla to the top-level Makefile"

* tag 'vla-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  Makefile: Globally enable VLA warning
  compiler.h: give up __compiletime_assert_fallback()
parents ac747c07 0bb95f80

Makefile

+3 −0
Original line number Diff line number Diff line
@@ -801,6 +801,9 @@ NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) 
# warn about C99 declaration after statement

KBUILD_CFLAGS += -Wdeclaration-after-statement



# Variable Length Arrays (VLAs) should not be used anywhere in the kernel

KBUILD_CFLAGS += $(call cc-option,-Wvla)



# disable pointer signed / unsigned warnings in gcc 4.0

KBUILD_CFLAGS += -Wno-pointer-sign

drivers/gpu/drm/i915/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ 
# Note the danger in using -Wall -Wextra is that when CI updates gcc we

# will most likely get a sudden build breakage... Hopefully we will fix

# new warnings before CI updates!

subdir-ccflags-y := -Wall -Wextra -Wvla

subdir-ccflags-y := -Wall -Wextra

subdir-ccflags-y += $(call cc-disable-warning, unused-parameter)

subdir-ccflags-y += $(call cc-disable-warning, type-limits)

subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers)

include/linux/compiler.h

+1 −16
Original line number Diff line number Diff line
@@ -344,29 +344,14 @@ static inline void *offset_to_ptr(const int *off) 
#endif

#ifndef __compiletime_error

# define __compiletime_error(message)

/*

 * Sparse complains of variable sized arrays due to the temporary variable in

 * __compiletime_assert. Unfortunately we can't just expand it out to make

 * sparse see a constant array size without breaking compiletime_assert on old

 * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.

 */

# ifndef __CHECKER__

#  define __compiletime_error_fallback(condition) \

	do { ((void)sizeof(char[1 - 2 * condition])); } while (0)

# endif

#endif

#ifndef __compiletime_error_fallback

# define __compiletime_error_fallback(condition) do { } while (0)

#endif



#ifdef __OPTIMIZE__

# define __compiletime_assert(condition, msg, prefix, suffix)		\

	do {								\

		int __cond = !(condition);				\

		extern void prefix ## suffix(void) __compiletime_error(msg); \

		if (__cond)						\

		if (!(condition))					\

			prefix ## suffix();				\

		__compiletime_error_fallback(__cond);			\

	} while (0)

#else

# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)

lib/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -53,7 +53,9 @@ obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o 
obj-$(CONFIG_TEST_IDA) += test_ida.o

obj-$(CONFIG_TEST_KASAN) += test_kasan.o

CFLAGS_test_kasan.o += -fno-builtin

CFLAGS_test_kasan.o += $(call cc-disable-warning, vla)

obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o

CFLAGS_test_ubsan.o += $(call cc-disable-warning, vla)

UBSAN_SANITIZE_test_ubsan.o := y

obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o

obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o

scripts/Makefile.extrawarn

+0 −1
Original line number Diff line number Diff line
@@ -52,7 +52,6 @@ warning-3 += -Wpointer-arith 
warning-3 += -Wredundant-decls

warning-3 += -Wswitch-default

warning-3 += $(call cc-option, -Wpacked-bitfield-compat)

warning-3 += $(call cc-option, -Wvla)



warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))

warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))