We already have xmalloc(), xcalloc(), and xrealloc((). Add xstrdup()
as well to save tedious error handling.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull more Kbuild updates from Masahiro Yamada:
"Makefile changes:
- enable unused-variable warning that was wrongly disabled for clang
Kconfig changes:
- warn about blank 'help' and fix existing instances
- fix 'choice' behavior to not write out invisible symbols
- fix misc weirdness
Coccinell changes:
- fix false positive of free after managed memory alloc detection
- improve performance of NULL dereference detection"
* tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
kconfig: remove const qualifier from sym_expand_string_value()
kconfig: add xrealloc() helper
kconfig: send error messages to stderr
kconfig: echo stdin to stdout if either is redirected
kconfig: remove check_stdin()
kconfig: remove 'config*' pattern from .gitignnore
kconfig: show '?' prompt even if no help text is available
kconfig: do not write choice values when their dependency becomes n
coccinelle: deref_null: avoid useless computation
coccinelle: devm_free: reduce false positives
kbuild: clang: disable unused variable warnings only when constant
kconfig: Warn if help text is blank
nios2: kconfig: Remove blank help text
arm: vt8500: kconfig: Remove blank help text
MIPS: kconfig: Remove blank help text
MIPS: BCM63XX: kconfig: Remove blank help text
lib/Kconfig.debug: Remove blank help text
Staging: rtl8192e: kconfig: Remove blank help text
Staging: rtl8192u: kconfig: Remove blank help text
mmc: kconfig: Remove blank help text
...
This function returns realloc'ed memory, so the returned pointer
must be passed to free() when done. So, 'const' qualifier is odd.
It is allowed to modify the expanded string.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
We already have xmalloc(), xcalloc(). Add xrealloc() as well
to save tedious error handling.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull gcc plugins updates from Kees Cook:
- update includes for gcc 8 (Valdis Kletnieks)
- update initializers for gcc 8
* tag 'gcc-plugins-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: Use dynamic initializers
gcc-plugins: Add include required by GCC release 8
If stdio is not tty, conf_askvalue() puts additional new line to
prevent prompts from being concatenated into a single line. This
care is missing in conf_choice(), so a 'choice' prompt and the next
prompt are shown in the same line.
Move the code into xfgets() to cater to all cases. To improve this
more, let's echo stdin to stdout. This clarifies what keys were
input from stdio and the stdout looks like as if it were from tty.
I removed the isatty(2) check since stderr is unrelated here.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
Except silentoldconfig, valid_stdin is 1, so check_stdin() is no-op.
oldconfig and silentoldconfig work almost in the same way except that
the latter generates additional files under include/. Both ask users
for input for new symbols.
I do not know why only silentoldconfig requires stdio be tty.
$ rm -f .config; touch .config
$ yes "" | make oldconfig > stdout
$ rm -f .config; touch .config
$ yes "" | make silentoldconfig > stdout
make[1]: *** [silentoldconfig] Error 1
make: *** [silentoldconfig] Error 2
$ tail -n 4 stdout
Console input/output is redirected. Run 'make oldconfig' to update configuration.
scripts/kconfig/Makefile:40: recipe for target 'silentoldconfig' failed
Makefile:507: recipe for target 'silentoldconfig' failed
Redirection is useful, for example, for testing where we want to give
particular key inputs from a test file, then check the result.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
I could not figure out why this pattern should be ignored.
Checking commit 1e65174a33 ("Add some basic .gitignore files")
did not help.
Let's remove this pattern, then see if it is really needed.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
'make config', 'make oldconfig', etc. always receive '?' as a valid
input and show useful information even if no help text is available.
------------------------>8------------------------
foo (FOO) [N/y] (NEW) ?
There is no help available for this option.
Symbol: FOO [=n]
Type : bool
Prompt: foo
Defined at Kconfig:1
------------------------>8------------------------
However, '?' is not shown in the prompt if its help text is missing.
Let's show '?' all the time so that the prompt and the behavior match.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
"# CONFIG_... is not set" for choice values are wrongly written into
the .config file if they are once visible, then become invisible later.
Test case
---------
---------------------------(Kconfig)----------------------------
config A
bool "A"
choice
prompt "Choice ?"
depends on A
config CHOICE_B
bool "Choice B"
config CHOICE_C
bool "Choice C"
endchoice
----------------------------------------------------------------
---------------------------(.config)----------------------------
CONFIG_A=y
----------------------------------------------------------------
With the Kconfig and .config above,
$ make config
scripts/kconfig/conf --oldaskconfig Kconfig
*
* Linux Kernel Configuration
*
A (A) [Y/n] n
#
# configuration written to .config
#
$ cat .config
#
# Automatically generated file; DO NOT EDIT.
# Linux Kernel Configuration
#
# CONFIG_A is not set
# CONFIG_CHOICE_B is not set
# CONFIG_CHOICE_C is not set
Here,
# CONFIG_CHOICE_B is not set
# CONFIG_CHOICE_C is not set
should not be written into the .config file because their dependency
"depends on A" is unmet.
Currently, there is no code that clears SYMBOL_WRITE of choice values.
Clear SYMBOL_WRITE for all symbols in sym_calc_value(), then set it
again after calculating visibility. To simplify the logic, set the
flag if they have non-n visibility, regardless of types, and regardless
of whether they are choice values or not.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
The effect of the rules ifm1, pr11, and pr12 is only used in the final rule,
which depends on context && !org && !report. Thus these rules should only
be performed in those circumstances.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Some files use both a non-devm allocation and a devm_allocation. Don't
complain about a free when the same function contains a non-devm
allocation.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
We get a lot of very large stack frames using gcc-7.0.1 with the default
-fsanitize-address-use-after-scope --param asan-stack=1 options, which can
easily cause an overflow of the kernel stack, e.g.
drivers/gpu/drm/i915/gvt/handlers.c:2434:1: warning: the frame size of 46176 bytes is larger than 3072 bytes
drivers/net/wireless/ralink/rt2x00/rt2800lib.c:5650:1: warning: the frame size of 23632 bytes is larger than 3072 bytes
lib/atomic64_test.c:250:1: warning: the frame size of 11200 bytes is larger than 3072 bytes
drivers/gpu/drm/i915/gvt/handlers.c:2621:1: warning: the frame size of 9208 bytes is larger than 3072 bytes
drivers/media/dvb-frontends/stv090x.c:3431:1: warning: the frame size of 6816 bytes is larger than 3072 bytes
fs/fscache/stats.c:287:1: warning: the frame size of 6536 bytes is larger than 3072 bytes
To reduce this risk, -fsanitize-address-use-after-scope is now split out
into a separate CONFIG_KASAN_EXTRA Kconfig option, leading to stack
frames that are smaller than 2 kilobytes most of the time on x86_64. An
earlier version of this patch also prevented combining KASAN_EXTRA with
KASAN_INLINE, but that is no longer necessary with gcc-7.0.1.
All patches to get the frame size below 2048 bytes with CONFIG_KASAN=y
and CONFIG_KASAN_EXTRA=n have been merged by maintainers now, so we can
bring back that default now. KASAN_EXTRA=y still causes lots of
warnings but now defaults to !COMPILE_TEST to disable it in
allmodconfig, and it remains disabled in all other defconfigs since it
is a new option. I arbitrarily raise the warning limit for KASAN_EXTRA
to 3072 to reduce the noise, but an allmodconfig kernel still has around
50 warnings on gcc-7.
I experimented a bit more with smaller stack frames and have another
follow-up series that reduces the warning limit for 64-bit architectures
to 1280 bytes (without CONFIG_KASAN).
With earlier versions of this patch series, I also had patches to address
the warnings we get with KASAN and/or KASAN_EXTRA, using a
"noinline_if_stackbloat" annotation.
That annotation now got replaced with a gcc-8 bugfix (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715) and a workaround for
older compilers, which means that KASAN_EXTRA is now just as bad as
before and will lead to an instant stack overflow in a few extreme
cases.
This reverts parts of commit 3f181b4d86 ("lib/Kconfig.debug: disable
-Wframe-larger-than warnings with KASAN=y"). Two patches in linux-next
should be merged first to avoid introducing warnings in an allmodconfig
build:
3cd890dbe2 ("media: dvb-frontends: fix i2c access helpers for KASAN")
16c3ada89c ("media: r820t: fix r820t_write_reg for KASAN")
Do we really need to backport this?
I think we do: without this patch, enabling KASAN will lead to
unavoidable kernel stack overflow in certain device drivers when built
with gcc-7 or higher on linux-4.10+ or any version that contains a
backport of commit c5caf21ab0. Most people are probably still on
older compilers, but it will get worse over time as they upgrade their
distros.
The warnings we get on kernels older than this should all be for code
that uses dangerously large stack frames, though most of them do not
cause an actual stack overflow by themselves.The asan-stack option was
added in linux-4.0, and commit 3f181b4d86 ("lib/Kconfig.debug:
disable -Wframe-larger-than warnings with KASAN=y") effectively turned
off the warning for allmodconfig kernels, so I would like to see this
fix backported to any kernels later than 4.0.
I have done dozens of fixes for individual functions with stack frames
larger than 2048 bytes with asan-stack, and I plan to make sure that
all those fixes make it into the stable kernels as well (most are
already there).
Part of the complication here is that asan-stack (from 4.0) was
originally assumed to always require much larger stacks, but that
turned out to be a combination of multiple gcc bugs that we have now
worked around and fixed, but sanitize-address-use-after-scope (from
v4.10) has a much higher inherent stack usage and also suffers from at
least three other problems that we have analyzed but not yet fixed
upstream, each of them makes the stack usage more severe than it should
be.
Link: http://lkml.kernel.org/r/20171221134744.2295529-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Similarly to type mismatch checks, new GCC 8.x and Clang also changed for
ABI for returns_nonnull checks. While we can update our code to conform
the new ABI it's more reasonable to just remove it. Because it's just
dead code, we don't have any single user of returns_nonnull attribute in
the whole kernel.
And AFAIU the advantage that this attribute could bring would be mitigated
by -fno-delete-null-pointer-checks cflag that we use to build the kernel.
So it's unlikely we will have a lot of returns_nonnull attribute in
future.
So let's just remove the code, it has no use.
[aryabinin@virtuozzo.com: fix warning]
Link: http://lkml.kernel.org/r/20180122165711.11510-1-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/20180119152853.16806-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Sodagudi Prasad <psodagud@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DEVICE_ATTR is a declaration macro that has a few alternate and
preferred forms like DEVICE_ATTR_RW, DEVICE_ATTR_RO, and DEVICE_ATTR.
As well, many uses of DEVICE_ATTR could use the preferred forms when the
show or store functions are also named in a regular form.
Suggest the preferred forms when appropriate.
Also emit a permissions warning if the the permissions are not the
typical 0644, 0444, or 0200.
Link: http://lkml.kernel.org/r/725864f363d91d1e1e6894a39fb57662eabd6d65.1513803306.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Masahiro Yamada
James Hogan
Peter Zijlstra
Linus Torvalds
Julia Lawall
Arnd Bergmann
Andrey Ryabinin
Joe Perches