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Filename Latest commit message Latest commit date
Joe Stringer c03567a8e8 include/linux/compiler.h: don't perform compiletime_assert with -O0
Commit c7acec713d ("kernel.h: handle pointers to arrays better in
container_of()") made use of __compiletime_assert() from container_of()
thus increasing the usage of this macro, allowing developers to notice
type conflicts in usage of container_of() at compile time.

However, the implementation of __compiletime_assert relies on compiler
optimizations to report an error.  This means that if a developer uses
"-O0" with any code that performs container_of(), the compiler will always
report an error regardless of whether there is an actual problem in the
code.

This patch disables compile_time_assert when optimizations are disabled to
allow such code to compile with CFLAGS="-O0".

Example compilation failure:

./include/linux/compiler.h:547:38: error: call to `__compiletime_assert_94' declared with attribute error: pointer type mismatch in container_of()
  _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
                                      ^
./include/linux/compiler.h:530:4: note: in definition of macro `__compiletime_assert'
    prefix ## suffix();    \
    ^~~~~~
./include/linux/compiler.h:547:2: note: in expansion of macro `_compiletime_assert'
  _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
  ^~~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:46:37: note: in expansion of macro `compiletime_assert'
 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                     ^~~~~~~~~~~~~~~~~~
./include/linux/kernel.h:860:2: note: in expansion of macro `BUILD_BUG_ON_MSG'
  BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
  ^~~~~~~~~~~~~~~~

[akpm@linux-foundation.org: use do{}while(0), per Michal]
Link: http://lkml.kernel.org/r/20170829230114.11662-1-joe@ovn.org
Fixes: c7acec713d ("kernel.h: handle pointers to arrays better in container_of()")
Signed-off-by: Joe Stringer <joe@ovn.org>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-31 16:33:15 -07:00
arch Merge branch 'for-linus-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2017-08-30 14:59:38 -07:00
block blk-mq-debugfs: Add names for recently added flags 2017-08-25 08:07:44 -06:00
certs
crypto
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-21 13:16:27 -07:00
drivers vmwgfx and core drm fixes 2017-08-30 15:10:56 -07:00
firmware
fs fs/select: Fix memory corruption in compat_get_fd_set() 2017-08-28 16:09:19 -07:00
include include/linux/compiler.h: don't perform compiletime_assert with -O0 2017-08-31 16:33:15 -07:00
init
ipc ipc: add missing container_of()s for randstruct 2017-08-02 17:16:12 -07:00
kernel mm, uprobes: fix multiple free of ->uprobes_state.xol_area 2017-08-31 16:33:15 -07:00
lib kernel/watchdog: Prevent false positives with turbo modes 2017-08-18 12:35:02 +02:00
mm mm, madvise: ensure poisoned pages are removed from per-cpu lists 2017-08-31 16:33:15 -07:00
net Two nfsd bugfixes, neither 4.13 regressions, but both potentially 2017-08-25 17:27:26 -07:00
samples samples/bpf: fix bpf tunnel cleanup 2017-07-31 22:02:47 -07:00
scripts Kbuild fixes for v4.13 2017-08-24 14:22:27 -07:00
security
sound ASoC: rt5677: Reintroduce I2C device IDs 2017-08-24 18:04:29 +02:00
tools NTB bug fixes to address an incorrect ntb_mw_count reference in the NTB 2017-08-27 17:01:54 -07:00
usr
virt KVM/ARM Fixes for v4.13-rc4 2017-08-03 17:59:58 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-08-20 09:07:56 -07:00
Makefile Linux 4.13-rc7 2017-08-27 17:20:40 -07:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.