The latest dtc update adds some new noisy warnings, so turn them off by
default. Disable 'avoid_unnecessary_addr_size' and 'alias_paths'. They
can be re-enabled by building with 'W=1'.
Signed-off-by: Rob Herring <robh@kernel.org>
This adds the following commits from upstream:
aadd0b65c987 checks: centralize printing of property names in failure messages
88960e398907 checks: centralize printing of node path in check_msg
f1879e1a50eb Add limited read-only support for older (V2 and V3) device tree to libfdt.
37dea76e9700 srcpos: drop special handling of tab
65893da4aee0 libfdt: overlay: Add missing license
962a45ca034d Avoid installing pylibfdt when dependencies are missing
cd6ea1b2bea6 Makefile: Split INSTALL out into INSTALL_{PROGRAM,LIB,DATA,SCRIPT}
51b3a16338df Makefile.tests: Add LIBDL make(1) variable for portability sake
333d533a8f4d Attempt to auto-detect stat(1) being used if not given proper invocation
e54388015af1 dtc: Bump version to v1.4.6
a1fe86f380cb fdtoverlay: Switch from using alloca to malloc
c8d5472de3ff tests: Improve compatibility with other platforms
c81d389a10cc checks: add chosen node checks
e671852042a7 checks: add aliases node checks
d0c44ebe3f42 checks: check for #{size,address}-cells without child nodes
18a3d84bb802 checks: add string list check for *-names properties
8fe94fd6f19f checks: add string list check
6c5730819604 checks: add a string check for 'label' property
a384191eba09 checks: fix sound-dai phandle with arg property check
b260c4f610c0 Fix ambiguous grammar for devicetree rule
fe667e382bac tests: Add some basic tests for the pci_bridge checks
7975f6422260 Fix widespread incorrect use of strneq(), replace with new strprefixeq()
fca296445eab Add strstarts() helper function
cc392f089007 tests: Check non-matching cases for fdt_node_check_compatible()
bba26a5291c8 livetree: avoid assertion of orphan phandles with overlays
c8f8194d76cc implement strnlen for systems that need it
c8b38f65fdec libfdt: Remove leading underscores from identifiers
3b62fdaebfe5 Remove leading underscores from identifiers
2d45d1c5c65e Replace FDT_VERSION() with stringify()
2e6fe5a107b5 Fix some errors in comments
b0ae9e4b0ceb tests: Correct warning in sw_tree1.c
Commit c8b38f65fdec upstream ("libfdt: Remove leading underscores from
identifiers") changed the multiple inclusion define protection, so the
kernel's libfdt_env.h needs the corresponding update.
Signed-off-by: Rob Herring <robh@kernel.org>
Now that the kernel build supports flex and bison, remove the _shipped
files and generate them during the build instead.
Based on Masahiro's original patch.
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Rob Herring <robh@kernel.org>
kconfig.h was excluded from consideration by fixdep by
6a5be57f0f (fixdep: fix extraneous dependencies) to avoid some false
positive hits
(1) include/config/.h
(2) include/config/h.h
(3) include/config/foo.h
(1) occurred because kconfig.h contains the string CONFIG_ in a
comment. However, since dee81e9886 (fixdep: faster CONFIG_ search), we
have a check that the part after CONFIG_ is non-empty, so this does not
happen anymore (and CONFIG_ appears by itself elsewhere, so that check
is worthwhile).
(2) comes from the include guard, __LINUX_KCONFIG_H. But with the
previous patch, we no longer match that either.
That leaves (3), which amounts to one [1] false dependency (aka stat() call
done by make), which I think we can live with:
We've already had one case [2] where the lack of include/linux/kconfig.h in
the .o.cmd file caused a missing rebuild, and while I originally thought
we should just put kconfig.h in the dependency list without parsing it
for the CONFIG_ pattern, we actually do have some real CONFIG_ symbols
mentioned in it, and one can imagine some translation unit that just
does '#ifdef __BIG_ENDIAN' but doesn't through some other header
actually depend on CONFIG_CPU_BIG_ENDIAN - so changing the target
endianness could end up rebuilding the world, minus that small
TU. Quoting Linus,
... when missing dependencies cause a missed re-compile, the resulting
bugs can be _really_ subtle.
[1] well, two, we now also have CONFIG_BOOGER/booger.h - we could change
that to FOO if we care
[2] https://lkml.org/lkml/2018/2/22/838
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The string CONFIG_ quite often appears after other alphanumerics,
meaning that that instance cannot be referencing a Kconfig
symbol. Omitting these means make has fewer files to stat() when
deciding what needs to be rebuilt - for a defconfig build, this seems to
remove about 2% of the (wildcard ...) lines from the .o.cmd files.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
uml-config.h hasn't existed in this decade (87e299e5c7 - x86, um: get
rid of uml-config.h). The few remaining UML_CONFIG instances are defined
directly in terms of their real CONFIG symbol in common-offsets.h, so
unlike when the symbols got defined via a sed script, anything that uses
UML_CONFIG_FOO now should also automatically pick up a dependency on
CONFIG_FOO via the normal fixdep mechanism (since common-offsets.h
should at least recursively be a dependency). Hence I believe we should
actually be able to ignore the HELLO_CONFIG_BOOM cases.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Richard Weinberger <richard@nod.at>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull Kbuild fixes from Masahiro Yamada:
- suppress sparse warnings about unknown attributes
- fix typos and stale comments
- fix build error of arch/sh
- fix wrong use of ld-option vs cc-ldoption
- remove redundant GCC_PLUGINS_CFLAGS assignment
- fix another memory leak of Kconfig
- fix line number in error messages of Kconfig
- do not write confusing CONFIG_DEFCONFIG_LIST out to .config
- add xstrdup() to Kconfig to handle memory shortage errors
- show also a Debian package name if ncurses is missing
* tag 'kbuild-fixes-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
MAINTAINERS: take over Kconfig maintainership
kconfig: fix line number in recursive inclusion error message
Coccinelle: memdup: Fix typo in warning messages
kconfig: Update ncurses package names for menuconfig
kbuild/kallsyms: trivial typo fix
kbuild: test --build-id linker flag by ld-option instead of cc-ldoption
kbuild: drop superfluous GCC_PLUGINS_CFLAGS assignment
kconfig: Don't leak choice names during parsing
sh: fix build error for empty CONFIG_BUILTIN_DTB_SOURCE
kconfig: set SYMBOL_AUTO to the symbol marked with defconfig_list
kconfig: add xstrdup() helper
kbuild: disable sparse warnings about unknown attributes
Makefile: Fix lying comment re. silentoldconfig
When recursive inclusion is detected, the line number of the last
'included from:' is wrong.
[Test Case]
Kconfig:
-------->8--------
source "Kconfig2"
-------->8--------
Kconfig2:
-------->8--------
source "Kconfig3"
-------->8--------
Kconfig3:
-------->8--------
source "Kconfig"
-------->8--------
[Result]
$ make allyesconfig
scripts/kconfig/conf --allyesconfig Kconfig
Kconfig:1: recursive inclusion detected. Inclusion path:
current file : 'Kconfig'
included from: 'Kconfig3:1'
included from: 'Kconfig2:1'
included from: 'Kconfig:3'
scripts/kconfig/Makefile:89: recipe for target 'allyesconfig' failed
make[1]: *** [allyesconfig] Error 1
Makefile:512: recipe for target 'allyesconfig' failed
make: *** [allyesconfig] Error 2
where we expect
current file : 'Kconfig'
included from: 'Kconfig3:1'
included from: 'Kconfig2:1'
included from: 'Kconfig:1'
The 'iter->lineno+1' in the second fpinrtf() should be 'iter->lineno-1'.
I refactored the code to merge the two fprintf() calls.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
GCC_PLUGINS_CFLAGS is already in the environment, so it is superfluous
to add it in commandline of final build of init/.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The named choice is not used in the kernel tree, but if it were used,
it would not be freed.
The intention of the named choice can be seen in the log of
commit 5a1aa8a1af ("kconfig: add named choice group").
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
The 'defconfig_list' is a weird attribute. If the '.config' is
missing, conf_read_simple() iterates over all visible defaults,
then it uses the first one for which fopen() succeeds.
config DEFCONFIG_LIST
string
depends on !UML
option defconfig_list
default "/lib/modules/$UNAME_RELEASE/.config"
default "/etc/kernel-config"
default "/boot/config-$UNAME_RELEASE"
default "$ARCH_DEFCONFIG"
default "arch/$ARCH/defconfig"
However, like other symbols, the first visible default is always
written out to the .config file. This might be different from what
has been actually used.
For example, on my machine, the third one "/boot/config-$UNAME_RELEASE"
is opened, like follows:
$ rm .config
$ make oldconfig 2>/dev/null
scripts/kconfig/conf --oldconfig Kconfig
#
# using defaults found in /boot/config-4.4.0-112-generic
#
*
* Restart config...
*
*
* IRQ subsystem
*
Expose irq internals in debugfs (GENERIC_IRQ_DEBUGFS) [N/y/?] (NEW)
However, the resulted .config file contains the first one since it is
visible:
$ grep CONFIG_DEFCONFIG_LIST .config
CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"
In order to stop confusing people, prevent this CONFIG option from
being written to the .config file.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
We can re-enable some dtc warnings that have been completely or mostly
fixed. There are a few remaining ones in arm64 dts files which crept in
recently.
Signed-off-by: Rob Herring <robh@kernel.org>
Commit eea199b445 ("kbuild: remove unnecessary LEX_PREFIX and
YACC_PREFIX") removed YACC_PREFIX definition, but left one use of it. There
was not any build error since there is no user of "cmd_bison_h" currently.
Remove the last remaining occurrence of YACC_PREFIX.
Fixes: eea199b445 ("kbuild: remove unnecessary LEX_PREFIX and YACC_PREFIX")
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Rob Herring <robh@kernel.org>
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>
So once upon a time I set out to fix the problem reported by Tobin wherein
a literal block within a kerneldoc comment would be corrupted in
processing. On the way, though, I got annoyed at the way I have to learn
how kernel-doc works from the beginning every time I tear into it.
As a result, seven of the following eight patches just get rid of some dead
code and reorganize the rest - mostly turning the 500-line process_file()
function into something a bit more rational. Sphinx output is unchanged
after these are applied. Then, at the end, there's a tweak to stop messing
with literal blocks.
If anybody was unaware that I've not done any serious Perl since the
1990's, they will certainly understand that fact now.
Add the SPDX header while I'm in the neighborhood. The source itself just
says "GNU General Public License", but it also refers people to the COPYING
file for further information. Since COPYING says 2.0-only, that is what I
have put into the header.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The parser at kernel-doc rejects names with dots in the middle.
Fix it, in order to support nested structs/unions.
Tested-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
When function description includes brackets after the function name as
suggested by Documentation/doc-guide/kernel-doc, the kernel-doc script
omits the function name from "Scanning doc for" report.
Extending match for identifier name with optional brackets fixes this
issue.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
It can be useful to put code snippets into kerneldoc comments; that can be
done with the "::" operator at the end of a line like this::
if (desperate)
run_in_circles();
The ".. code-block::" directive can also be used to this end. kernel-doc
currently fails to understand these literal blocks and applies its normal
markup to them, which is then treated as literal by sphinx. The result is
unsightly markup instead of a useful code snippet.
Apply a hack to the output code to recognize literal blocks and avoid
performing any special markup on them. It's ugly, but that means it fits
in well with the rest of the script.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Move STATE_INLINE and STATE_DOCBLOCK code out of process_file(), which now
actually fits on a single screen. Delete an unused variable and add a
couple of comments while I'm at it.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Move the top-level prototype-processing code out of process_file().
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Also group the pseudo-global $leading_space variable with its peers.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Move this code out of process_file() in the name of readability and
maintainability.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Begin the process of splitting up the nearly 500-line process_file()
function by moving STATE_NORMAL processing to a separate function.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
STATE_FIELD describes a parser state that can handle any part of a
kerneldoc comment body; rename it to STATE_BODY to reflect that.
The $in_purpose variable was a hidden substate of STATE_FIELD; get rid of
it and make a proper state (STATE_BODY_MAYBE) instead. This will make the
subsequent process_file() splitup easier.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
XML escaping is a worry that came with DocBook, which we no longer have any
dealings with. So get rid of the useless xml_escape()/xml_unescape()
functions. No change to the generated output.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Instead of asking the user to copy and paste a small perl script from
the documentation, just distribute the perl script in the scripts
directory.
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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>
