whiterose

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commit 746bb4ed6d626f3f9e431a7f9b20504538e62ded
parent ac747c0715f29c2be3848b719a1b7e65b07f7b21
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun, 28 Oct 2018 13:26:45 -0700

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()

Diffstat:
MMakefile | 3+++
Mdrivers/gpu/drm/i915/Makefile | 2+-
Minclude/linux/compiler.h | 17+----------------
Mlib/Makefile | 2++
Mscripts/Makefile.extrawarn | 1-
5 files changed, 7 insertions(+), 18 deletions(-)

diff --git a/Makefile b/Makefile @@ -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 diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile @@ -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 += $(call cc-disable-warning, missing-field-initializers) diff --git a/include/linux/compiler.h b/include/linux/compiler.h @@ -344,29 +344,14 @@ static inline void *offset_to_ptr(const int *off) #endif #ifndef __compiletime_error # define __compiletime_error(message) -/* - * Sparse complains of variable sized arrays due to the temporary variable in - * __compiletime_assert. Unfortunately we can't just expand it out to make - * sparse see a constant array size without breaking compiletime_assert on old - * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether. - */ -# ifndef __CHECKER__ -# define __compiletime_error_fallback(condition) \ - do { ((void)sizeof(char[1 - 2 * condition])); } while (0) -# endif -#endif -#ifndef __compiletime_error_fallback -# define __compiletime_error_fallback(condition) do { } while (0) #endif #ifdef __OPTIMIZE__ # define __compiletime_assert(condition, msg, prefix, suffix) \ do { \ - int __cond = !(condition); \ extern void prefix ## suffix(void) __compiletime_error(msg); \ - if (__cond) \ + if (!(condition)) \ prefix ## suffix(); \ - __compiletime_error_fallback(__cond); \ } while (0) #else # define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0) diff --git a/lib/Makefile b/lib/Makefile @@ -53,7 +53,9 @@ obj-$(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 diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn @@ -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)))