Revision 3dbae15538972c9e1578cb216964c2840361a538 authored by Gustavo A. R. Silva on 15 February 2020, 01:03:12 UTC, committed by Dmitry Torokhov on 15 February 2020, 01:19:22 UTC
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: https://lore.kernel.org/r/20200214172132.GA28389@embeddedor Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
1 parent 94bef5d
Makefile
# SPDX-License-Identifier: GPL-2.0
###
# scripts contains sources for various helper programs used throughout
# the kernel for the build process.
# ---------------------------------------------------------------------------
# kallsyms: Find all symbols in vmlinux
# conmakehash: Create chartable
# conmakehash: Create arrays for initializing the kernel console tables
HOST_EXTRACFLAGS += -I$(srctree)/tools/include
hostprogs-$(CONFIG_BUILD_BIN2C) += bin2c
hostprogs-$(CONFIG_KALLSYMS) += kallsyms
hostprogs-$(CONFIG_VT) += conmakehash
hostprogs-$(BUILD_C_RECORDMCOUNT) += recordmcount
hostprogs-$(CONFIG_BUILDTIME_EXTABLE_SORT) += sortextable
hostprogs-$(CONFIG_ASN1) += asn1_compiler
hostprogs-$(CONFIG_MODULE_SIG_FORMAT) += sign-file
hostprogs-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += extract-cert
hostprogs-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert
HOSTCFLAGS_sortextable.o = -I$(srctree)/tools/include
HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
HOSTLDLIBS_sign-file = -lcrypto
HOSTLDLIBS_extract-cert = -lcrypto
always := $(hostprogs-y) $(hostprogs-m)
# The following hostprogs-y programs are only build on demand
hostprogs-y += unifdef
subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins
subdir-$(CONFIG_MODVERSIONS) += genksyms
subdir-$(CONFIG_SECURITY_SELINUX) += selinux
# Let clean descend into subdirs
subdir- += basic dtc gdb kconfig mod
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