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()

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