When building a specific target such as bzImage, modules aren't normally
built. However if CONFIG_TRIM_UNUSED_KSYMS is enabled, no built modules
means none of the exported symbols are used and therefore they will all
be trimmed away from the final kernel. A subsequent "make modules" will
fail because modpost cannot find the needed symbols for those modules in
the kernel binary.
Let's make sure modules are also built whenever CONFIG_TRIM_UNUSED_KSYMS
is enabled and that the kernel binary is properly rebuilt accordingly.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some people are able to trigger a race where autoksyms.h is used before
its empty version is even created. Let's create it at the same time as
the directory holding it is created.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Tested-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull kbuild fixes from Michal Marek:
"Here are some regression fixes for kbuild:
- modversion support for exported asm symbols (Nick Piggin). The
affected architectures need separate patches adding
asm-prototypes.h.
- fix rebuilds of lib-ksyms.o (Nick Piggin)
- -fno-PIE builds (Sebastian Siewior and Borislav Petkov). This is
not a kernel regression, but one of the Debian gcc package.
Nevertheless, it's quite annoying, so I think it should go into
mainline and stable now"
* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kbuild: Steal gcc's pie from the very beginning
kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL
x86/kexec: add -fno-PIE
scripts/has-stack-protector: add -fno-PIE
kbuild: add -fno-PIE
kbuild: modversions for EXPORT_SYMBOL() for asm
kbuild: prevent lib-ksyms.o rebuilds
So Sebastian turned off the PIE for kernel builds but that was too late
- Kbuild.include already uses KBUILD_CFLAGS and trying to disable gcc
options with, say cc-disable-warning, fails:
gcc -D__KERNEL__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs
...
-Wno-sign-compare -fno-asynchronous-unwind-tables -Wframe-address -c -x c /dev/null -o .31392.tmp
/dev/null:1:0: error: code model kernel does not support PIC mode
because that returns an error and we can't disable the warning. For
example in this case:
KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,)
which leads to gcc issuing all those warnings again.
So let's turn off PIE/PIC at the earliest possible moment, when we
declare KBUILD_CFLAGS so that cc-disable-warning picks it up too.
Also, we need the $(call cc-option ...) because -fno-PIE is supported
since gcc v3.4 and our lowest supported gcc version is 3.2 right now.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Michal Marek <mmarek@suse.com>
Traditionally, we have always had warnings about uninitialized variables
enabled, as this is part of -Wall, and generally a good idea [1], but it
also always produced false positives, mainly because this is a variation
of the halting problem and provably impossible to get right in all cases
[2].
Various people have identified cases that are particularly bad for false
positives, and in commit e74fc973b6 ("Turn off -Wmaybe-uninitialized
when building with -Os"), I turned off the warning for any build that
was done with CC_OPTIMIZE_FOR_SIZE. This drastically reduced the number
of false positive warnings in the default build but unfortunately had
the side effect of turning the warning off completely in 'allmodconfig'
builds, which in turn led to a lot of warnings (both actual bugs, and
remaining false positives) to go in unnoticed.
With commit 877417e6ff ("Kbuild: change CC_OPTIMIZE_FOR_SIZE
definition") enabled the warning again for allmodconfig builds in v4.7
and in v4.8-rc1, I had finally managed to address all warnings I get in
an ARM allmodconfig build and most other maybe-uninitialized warnings
for ARM randconfig builds.
However, commit 6e8d666e92 ("Disable "maybe-uninitialized" warning
globally") was merged at the same time and disabled it completely for
all configurations, because of false-positive warnings on x86 that I had
not addressed until then. This caused a lot of actual bugs to get
merged into mainline, and I sent several dozen patches for these during
the v4.9 development cycle. Most of these are actual bugs, some are for
correct code that is safe because it is only called under external
constraints that make it impossible to run into the case that gcc sees,
and in a few cases gcc is just stupid and finds something that can
obviously never happen.
I have now done a few thousand randconfig builds on x86 and collected
all patches that I needed to address every single warning I got (I can
provide the combined patch for the other warnings if anyone is
interested), so I hope we can get the warning back and let people catch
the actual bugs earlier.
This reverts the change to disable the warning completely and for now
brings it back at the "make W=1" level, so we can get it merged into
mainline without introducing false positives. A follow-up patch enables
it on all levels unless some configuration option turns it off because
of false-positives.
Link: https://rusty.ozlabs.org/?p=232 [1]
Link: https://gcc.gnu.org/wiki/Better_Uninitialized_Warnings [2]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Debian started to build the gcc with -fPIE by default so the kernel
build ends before it starts properly with:
|kernel/bounds.c:1:0: error: code model kernel does not support PIC mode
Also add to KBUILD_AFLAGS due to:
|gcc -Wp,-MD,arch/x86/entry/vdso/vdso32/.note.o.d … -mfentry -DCC_USING_FENTRY … vdso/vdso32/note.S
|arch/x86/entry/vdso/vdso32/note.S:1:0: sorry, unimplemented: -mfentry isn’t supported for 32-bit in combination with -fpic
Tagging it stable so it is possible to compile recent stable kernels as
well.
Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Michal Marek <mmarek@suse.com>
This update consists of:
- Fixes and improvements to existing tests
- Moving code from Documentation to selftests, samples, and tools.
Moves dnotify_test, prctl, ptp, vDSO, ia64, watchdog, and networking
tests from Documentation to selftests.
Moves mic/mpssd, misc-devices/mei, timers, watchdog, auxdisplay, and
blackfin examples from Documentation to samples.
Moves accounting, laptops/dslm, and pcmcia/crc32hash tools from
Documentation to tools.
Deletes BUILD_DOCSRC and its dependencies.
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Merge tag 'linux-kselftest-4.9-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull kselftest updates from Shuah Khan:
"This update consists of:
- Fixes and improvements to existing tests
- Moving code from Documentation to selftests, samples, and tools:
* Moves dnotify_test, prctl, ptp, vDSO, ia64, watchdog, and
networking tests from Documentation to selftests.
* Moves mic/mpssd, misc-devices/mei, timers, watchdog, auxdisplay,
and blackfin examples from Documentation to samples.
* Moves accounting, laptops/dslm, and pcmcia/crc32hash tools from
Documentation to tools.
* Deletes BUILD_DOCSRC and its dependencies"
* tag 'linux-kselftest-4.9-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (21 commits)
selftests/futex: Check ANSI terminal color support
Doc: update 00-INDEX files to reflect the runnable code move
samples: move blackfin gptimers-example from Documentation
tools: move pcmcia crc32hash tool from Documentation
tools: move laptops dslm tool from Documentation
tools: move accounting tool from Documentation
samples: move auxdisplay example code from Documentation
samples: move watchdog example code from Documentation
samples: move timers example code from Documentation
samples: move misc-devices/mei example code from Documentation
samples: move mic/mpssd example code from Documentation
selftests: Move networking/timestamping from Documentation
selftests: move watchdog tests from Documentation/watchdog
selftests: move ia64 tests from Documentation/ia64
selftests: move vDSO tests from Documentation/vDSO
selftests: move ptp tests from Documentation/ptp
selftests: move prctl tests from Documentation/prctl
selftests: move dnotify_test from Documentation/filesystems
selftests/timers: Add missing error code assignment before test
selftests/zram: replace ZRAM_LZ4_COMPRESS
...
Pull kbuild updates from Michal Marek:
- EXPORT_SYMBOL for asm source by Al Viro.
This does bring a regression, because genksyms no longer generates
checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is
working on a patch to fix this.
Plus, we are talking about functions like strcpy(), which rarely
change prototypes.
- Fixes for PPC fallout of the above by Stephen Rothwell and Nick
Piggin
- fixdep speedup by Alexey Dobriyan.
- preparatory work by Nick Piggin to allow architectures to build with
-ffunction-sections, -fdata-sections and --gc-sections
- CONFIG_THIN_ARCHIVES support by Stephen Rothwell
- fix for filenames with colons in the initramfs source by me.
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits)
initramfs: Escape colons in depfile
ppc: there is no clear_pages to export
powerpc/64: whitelist unresolved modversions CRCs
kbuild: -ffunction-sections fix for archs with conflicting sections
kbuild: add arch specific post-link Makefile
kbuild: allow archs to select link dead code/data elimination
kbuild: allow architectures to use thin archives instead of ld -r
kbuild: Regenerate genksyms lexer
kbuild: genksyms fix for typeof handling
fixdep: faster CONFIG_ search
ia64: move exports to definitions
sparc32: debride memcpy.S a bit
[sparc] unify 32bit and 64bit string.h
sparc: move exports to definitions
ppc: move exports to definitions
arm: move exports to definitions
s390: move exports to definitions
m68k: move exports to definitions
alpha: move exports to actual definitions
x86: move exports to actual definitions
...
This affectively reverts commit 377ccbb483 ("Makefile: Mute warning
for __builtin_return_address(>0) for tracing only") because it turns out
that it really isn't tracing only - it's all over the tree.
We already also had the warning disabled separately for mm/usercopy.c
(which this commit also removes), and it turns out that we will also
want to disable it for get_lock_parent_ip(), that is used for at least
TRACE_IRQFLAGS. Which (when enabled) ends up being all over the tree.
Steven Rostedt had a patch that tried to limit it to just the config
options that actually triggered this, but quite frankly, the extra
complexity and abstraction just isn't worth it. We have never actually
had a case where the warning is actually useful, so let's just disable
it globally and not worry about it.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move blackfin gptimers-example to samples and remove it from Documentation
Makefile. Update samples Kconfig and Makefile to build gptimers-example.
blackfin is the last CONFIG_BUILD_DOCSRC target in Documentation/Makefile.
Hence this patch also includes changes to remove CONFIG_BUILD_DOCSRC from
Makefile and lib/Kconfig.debug and updates VIDEO_PCI_SKELETON dependency
on BUILD_DOCSRC.
Documentation/Makefile is not deleted to avoid braking make htmldocs and
make distclean.
Acked-by: Michal Marek <mmarek@suse.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reported-by: Valentin Rothberg <valentinrothberg@gmail.com>
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
The Sphinx transition is still creating a fair amount of work. Here we
have a number of fixes and, importantly, a proper PDF output solution,
thanks to Jani Nikula, Mauro Carvalho Chehab and Markus Heiser.
I've started a couple of new books: a driver API book (based on the old
device-drivers.tmpl) and a development tools book. Both are meant to show
how we can integrate together our existing documentation into a more
coherent and accessible whole. It involves moving some stuff around and
formatting changes, but, I think, the results are worth it. The good news
is that most of our existing Documentation/*.txt files are *almost* in RST
format already; the amount of messing around required is minimal.
And, of course, there's the usual set of updates, typo fixes, and more.
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Merge tag 'docs-4.9' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"This is the documentation update pull for the 4.9 merge window.
The Sphinx transition is still creating a fair amount of work. Here we
have a number of fixes and, importantly, a proper PDF output solution,
thanks to Jani Nikula, Mauro Carvalho Chehab and Markus Heiser.
I've started a couple of new books: a driver API book (based on the
old device-drivers.tmpl) and a development tools book. Both are meant
to show how we can integrate together our existing documentation into
a more coherent and accessible whole. It involves moving some stuff
around and formatting changes, but, I think, the results are worth it.
The good news is that most of our existing Documentation/*.txt files
are *almost* in RST format already; the amount of messing around
required is minimal.
And, of course, there's the usual set of updates, typo fixes, and
more"
* tag 'docs-4.9' of git://git.lwn.net/linux: (120 commits)
URL changed for Linux Foundation TAB
dax : Fix documentation with respect to struct pages
iio: Documentation: Correct the path used to create triggers.
docs: Remove space-before-label guidance from CodingStyle
docs-rst: add inter-document cross references
Documentation/email-clients.txt: convert it to ReST markup
Documentation/kernel-docs.txt: reorder based on timestamp
Documentation/kernel-docs.txt: Add dates for online docs
Documentation/kernel-docs.txt: get rid of broken docs
Documentation/kernel-docs.txt: move in-kernel docs
Documentation/kernel-docs.txt: remove more legacy references
Documentation/kernel-docs.txt: add two published books
Documentation/kernel-docs.txt: sort books per publication date
Documentation/kernel-docs.txt: adjust LDD references
Documentation/kernel-docs.txt: some improvements on the ReST output
Documentation/kernel-docs.txt: Consistent indenting: 4 spaces
Documentation/kernel-docs.txt: Add 4 paper/book references
Documentation/kernel-docs.txt: Improve layouting of book list
Documentation/kernel-docs.txt: Remove offline or outdated entries
docs: Clean up bare :: lines
...
Allow architectures to create arch/xxx/Makefile.postlink with targets
for vmlinux, modules.ko, and clean, which will be invoked after final
linking of vmlinux and modules.
powerpc will use this to check vmlinux linker relocations for sanity,
and may use it to fix up alternate instruction patch branch addresses.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Introduce LD_DEAD_CODE_DATA_ELIMINATION option for architectures to
select to build with -ffunction-sections, -fdata-sections, and link
with --gc-sections. It requires some work (documented) to ensure all
unreferenced entrypoints are live, and requires toolchain and build
verification, so it is made a per-arch option for now.
On a random powerpc64le build, this yelds a significant size saving,
it boots and runs fine, but there is a lot I haven't tested as yet, so
these savings may be reduced if there are bugs in the link.
text data bss dec filename
11169741 1180744 1923176 14273661 vmlinux
10445269 1004127 1919707 13369103 vmlinux.dce
~700K text, ~170K data, 6% removed from kernel image size.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Sphinx supports LaTeX output. Sometimes, it is interesting to
call it directly, instead of also generating a PDF. As it comes
for free, add a target for it.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
When the compiler doesn't support gcc plugins (either due to missing
headers or too old a version), report the problem and abort the build
instead of emitting a warning and letting the build founder with arcane
compiler errors.
Signed-off-by: Kees Cook <keescook@chromium.org>
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Merge tag 'media/v4.8-5' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media DocBook removal and some fixups from Mauro Carvalho Chehab:
- removal of the media DocBook (since it's all in Sphinx now)
- videobuf2: Fix an allocation regression
- a few fixes related to the CEC drivers
* tag 'media/v4.8-5' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] cec: fix off-by-one memset
[media] staging: add MEDIA_SUPPORT dependency
[media] vivid: don't handle CEC_MSG_SET_STREAM_PATH
[media] media: adv7180: Fix broken interrupt register access
[media] vb2: Fix allocation size of dma_parms
[media] vim2m: copy the other colorspace-related fields as well
[media] adv7511: fix VIC autodetect
doc-rst: Remove the media docbook
. Move the suppressing of the __builtin_return_address >0 warning to the
tracing directory only.
. metag recordmcount fix for newer glibc's
. Two tracing histogram fixes that were reported by KASAN
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Merge tag 'trace-v4.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"A few updates and fixes:
- move the suppressing of the __builtin_return_address >0 warning to
the tracing directory only.
- metag recordmcount fix for newer glibc's
- two tracing histogram fixes that were reported by KASAN"
* tag 'trace-v4.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix use-after-free in hist_register_trigger()
tracing: Fix use-after-free in hist_unreg_all/hist_enable_unreg_all
Makefile: Mute warning for __builtin_return_address(>0) for tracing only
ftrace/recordmcount: Work around for addition of metag magic but not relocations
Pull kbuild updates from Michal Marek:
- GCC plugin support by Emese Revfy from grsecurity, with a fixup from
Kees Cook. The plugins are meant to be used for static analysis of
the kernel code. Two plugins are provided already.
- reduction of the gcc commandline by Arnd Bergmann.
- IS_ENABLED / IS_REACHABLE macro enhancements by Masahiro Yamada
- bin2c fix by Michael Tautschnig
- setlocalversion fix by Wolfram Sang
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
gcc-plugins: disable under COMPILE_TEST
kbuild: Abort build on bad stack protector flag
scripts: Fix size mismatch of kexec_purgatory_size
kbuild: make samples depend on headers_install
Kbuild: don't add obj tree in additional includes
Kbuild: arch: look for generated headers in obtree
Kbuild: always prefix objtree in LINUXINCLUDE
Kbuild: avoid duplicate include path
Kbuild: don't add ../../ to include path
vmlinux.lds.h: replace config_enabled() with IS_ENABLED()
kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
kconfig.h: use already defined macros for IS_REACHABLE() define
export.h: use __is_defined() to check if __KSYM_* is defined
kconfig.h: use __is_defined() to check if MODULE is defined
kbuild: setlocalversion: print error to STDERR
Add sancov plugin
Add Cyclomatic complexity GCC plugin
GCC plugin infrastructure
Shared library support
With the latest gcc compilers, they give a warning if
__builtin_return_address() parameter is greater than 0. That is because if
it is used by a function called by a top level function (or in the case of
the kernel, by assembly), it can try to access stack frames outside the
stack and crash the system.
The tracing system uses __builtin_return_address() of up to 2! But it is
well aware of the dangers that it may have, and has even added precautions
to protect against it (see the thunk code in arch/x86/entry/thunk*.S)
Linus originally added KBUILD_CFLAGS that would suppress the warning for the
entire kernel, as simply adding KBUILD_CFLAGS to the tracing directory
wouldn't work. The tracing directory plays a bit with the CFLAGS and
requires a little more logic.
This adds that special logic to only suppress the warning for the tracing
directory. If it is used anywhere else outside of tracing, the warning will
still be triggered.
Link: http://lkml.kernel.org/r/20160728223043.51996267@grimm.local.home
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Now that all media documentation was converted to Sphinx, we
should get rid of the old DocBook one, as we don't want people
to submit patches against the old stuff.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Newer versions of gcc warn about the use of __builtin_return_address()
with a non-zero argument when "-Wall" is specified:
kernel/trace/trace_irqsoff.c: In function ‘stop_critical_timings’:
kernel/trace/trace_irqsoff.c:433:86: warning: calling ‘__builtin_return_address’ with a nonzero argument is unsafe [-Wframe-address]
stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
[ .. repeats a few times for other similar cases .. ]
It is true that a non-zero argument is somewhat dangerous, and we do not
actually have very many uses of that in the kernel - but the ftrace code
does use it, and as Stephen Rostedt says:
"We are well aware of the danger of using __builtin_return_address() of
> 0. In fact that's part of the reason for having the "thunk" code in
x86 (See arch/x86/entry/thunk_{64,32}.S). [..] it adds extra frames
when tracking irqs off sections, to prevent __builtin_return_address()
from accessing bad areas. In fact the thunk_32.S states: 'Trampoline to
trace irqs off. (otherwise CALLER_ADDR1 might crash)'."
For now, __builtin_return_address() with a non-zero argument is the best
we can do, and the warning is not helpful and can end up making people
miss other warnings for real problems.
So disable the frame-address warning on compilers that need it.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Several build configurations had already disabled this warning because
it generates a lot of false positives. But some had not, and it was
still enabled for "allmodconfig" builds, for example.
Looking at the warnings produced, every single one I looked at was a
false positive, and the warnings are frequent enough (and big enough)
that they can easily hide real problems that you don't notice in the
noise generated by -Wmaybe-uninitialized.
The warning is good in theory, but this is a classic case of a warning
that causes more problems than the warning can solve.
If gcc gets better at avoiding false positives, we may be able to
re-enable this warning. But as is, we're better off without it, and I
want to be able to see the *real* warnings.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge updates from Andrew Morton:
- a few misc bits
- ocfs2
- most(?) of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (125 commits)
thp: fix comments of __pmd_trans_huge_lock()
cgroup: remove unnecessary 0 check from css_from_id()
cgroup: fix idr leak for the first cgroup root
mm: memcontrol: fix documentation for compound parameter
mm: memcontrol: remove BUG_ON in uncharge_list
mm: fix build warnings in <linux/compaction.h>
mm, thp: convert from optimistic swapin collapsing to conservative
mm, thp: fix comment inconsistency for swapin readahead functions
thp: update Documentation/{vm/transhuge,filesystems/proc}.txt
shmem: split huge pages beyond i_size under memory pressure
thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE
khugepaged: add support of collapse for tmpfs/shmem pages
shmem: make shmem_inode_info::lock irq-safe
khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page()
thp: extract khugepaged from mm/huge_memory.c
shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings
shmem: add huge pages support
shmem: get_unmapped_area align huge page
shmem: prepare huge= mount option and sysfs knob
mm, rmap: account shmem thp pages
...
Before, the stack protector flag was sanity checked before .config had
been reprocessed. This meant the build couldn't be aborted early, and
only a warning could be emitted followed later by the compiler blowing
up with an unknown flag. This has caused a lot of confusion over time,
so this splits the flag selection from sanity checking and performs the
sanity checking after the make has been restarted from a reprocessed
.config, so builds can be aborted as early as possible now.
Additionally moves the x86-specific sanity check to the same location,
since it suffered from the same warn-then-wait-for-compiler-failure
problem.
Link: http://lkml.kernel.org/r/20160712223043.GA11664@www.outflux.net
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before, the stack protector flag was sanity checked before .config had
been reprocessed. This meant the build couldn't be aborted early, and
only a warning could be emitted followed later by the compiler blowing
up with an unknown flag. This has caused a lot of confusion over time,
so this splits the flag selection from sanity checking and performs the
sanity checking after the make has been restarted from a reprocessed
.config, so builds can be aborted as early as possible now.
Additionally moves the x86-specific sanity check to the same location,
since it suffered from the same warn-then-wait-for-compiler-failure
problem.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
documentation mechanism based on the Sphinx system. The objectives here
are to make it easier to create better-integrated (and more attractive)
documents while (eventually) dumping our one-of-a-kind, cobbled-together
system for something that is widely used and maintained by others. There's
a fair amount of information what's being done, why, and how to use it in:
https://lwn.net/Articles/692704/https://lwn.net/Articles/692705/
Closer to home, Documentation/kernel-documentation.rst describes how it
works.
For now, the new system exists alongside the old one; you should soon see
the GPU documentation converted over in the DRM pull and some significant
media conversion work as well. Once all the docs have been moved over and
we're convinced that the rough edges (of which are are a few) have been
smoothed over, the DocBook-based stuff should go away.
Primary credit is to Jani Nikula for doing the heavy lifting to make this
stuff actually work; there has also been notable effort from Markus Heiser,
Daniel Vetter, and Mauro Carvalho Chehab.
Expect a couple of conflicts on the new index.rst file over the course of
the merge window; they are trivially resolvable. That file may be a bit of
a conflict magnet in the short term, but I don't expect that situation to
last for any real length of time.
Beyond that, of course, we have the usual collection of tweaks, updates,
and typo fixes.
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Merge tag 'docs-for-linus' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"Some big changes this month, headlined by the addition of a new
formatted documentation mechanism based on the Sphinx system.
The objectives here are to make it easier to create better-integrated
(and more attractive) documents while (eventually) dumping our
one-of-a-kind, cobbled-together system for something that is widely
used and maintained by others. There's a fair amount of information
what's being done, why, and how to use it in:
https://lwn.net/Articles/692704/https://lwn.net/Articles/692705/
Closer to home, Documentation/kernel-documentation.rst describes how
it works.
For now, the new system exists alongside the old one; you should soon
see the GPU documentation converted over in the DRM pull and some
significant media conversion work as well. Once all the docs have
been moved over and we're convinced that the rough edges (of which are
are a few) have been smoothed over, the DocBook-based stuff should go
away.
Primary credit is to Jani Nikula for doing the heavy lifting to make
this stuff actually work; there has also been notable effort from
Markus Heiser, Daniel Vetter, and Mauro Carvalho Chehab.
Expect a couple of conflicts on the new index.rst file over the course
of the merge window; they are trivially resolvable. That file may be
a bit of a conflict magnet in the short term, but I don't expect that
situation to last for any real length of time.
Beyond that, of course, we have the usual collection of tweaks,
updates, and typo fixes"
* tag 'docs-for-linus' of git://git.lwn.net/linux: (77 commits)
doc-rst: kernel-doc: fix handling of address_space tags
Revert "doc/sphinx: Enable keep_warnings"
doc-rst: kernel-doc directive, fix state machine reporter
docs: deprecate kernel-doc-nano-HOWTO.txt
doc/sphinx: Enable keep_warnings
Documentation: add watermark_scale_factor to the list of vm systcl file
kernel-doc: Fix up warning output
docs: Get rid of some kernel-documentation warnings
doc-rst: add an option to ignore DocBooks when generating docs
workqueue: Fix a typo in workqueue.txt
Doc: ocfs: Fix typo in filesystems/ocfs2-online-filecheck.txt
Documentation/sphinx: skip build if user requested specific DOCBOOKS
Documentation: add cleanmediadocs to the documentation targets
Add .pyc files to .gitignore
Doc: PM: Fix a typo in intel_powerclamp.txt
doc-rst: flat-table directive - initial implementation
Documentation: add meta-documentation for Sphinx and kernel-doc
Documentation: tiny typo fix in usb/gadget_multi.txt
Documentation: fix wrong value in md.txt
bcache: documentation formatting, edited for clarity, stripe alignment notes
...
Pull perf updates from Ingo Molnar:
"With over 300 commits it's been a busy cycle - with most of the work
concentrated on the tooling side (as it should).
The main kernel side enhancements were:
- Add per event callchain limit: Recently we introduced a sysctl to
tune the max-stack for all events for which callchains were
requested:
$ sysctl kernel.perf_event_max_stack
kernel.perf_event_max_stack = 127
Now this patch introduces a way to configure this per event, i.e.
this becomes possible:
$ perf record -e sched:*/max-stack=2/ -e block:*/max-stack=10/ -a
allowing finer tuning of how much buffer space callchains use.
This uses an u16 from the reserved space at the end, leaving
another u16 for future use.
There has been interest in even finer tuning, namely to control the
max stack for kernel and userspace callchains separately. Further
discussion is needed, we may for instance use the remaining u16 for
that and when it is present, assume that the sample_max_stack
introduced in this patch applies for the kernel, and the u16 left
is used for limiting the userspace callchain (Arnaldo Carvalho de
Melo)
- Optimize AUX event (hardware assisted side-band event) delivery
(Kan Liang)
- Rework Intel family name macro usage (this is partially x86 arch
work) (Dave Hansen)
- Refine and fix Intel LBR support (David Carrillo-Cisneros)
- Add support for Intel 'TopDown' events (Andi Kleen)
- Intel uncore PMU driver fixes and enhancements (Kan Liang)
- ... other misc changes.
Here's an incomplete list of the tooling enhancements (but there's
much more, see the shortlog and the git log for details):
- Support cross unwinding, i.e. collecting '--call-graph dwarf'
perf.data files in one machine and then doing analysis in another
machine of a different hardware architecture. This enables, for
instance, to do:
$ perf record -a --call-graph dwarf
on a x86-32 or aarch64 system and then do 'perf report' on it on a
x86_64 workstation (He Kuang)
- Allow reading from a backward ring buffer (one setup via
sys_perf_event_open() with perf_event_attr.write_backward = 1)
(Wang Nan)
- Finish merging initial SDT (Statically Defined Traces) support, see
cset comments for details about how it all works (Masami Hiramatsu)
- Support attaching eBPF programs to tracepoints (Wang Nan)
- Add demangling of symbols in programs written in the Rust language
(David Tolnay)
- Add support for tracepoints in the python binding, including an
example, that sets up and parses sched:sched_switch events,
tools/perf/python/tracepoint.py (Jiri Olsa)
- Introduce --stdio-color to set up the color output mode selection
in 'annotate' and 'report', allowing emit color escape sequences
when redirecting the output of these tools (Arnaldo Carvalho de
Melo)
- Add 'callindent' option to 'perf script -F', to indent the Intel PT
call stack, making this output more ftrace-like (Adrian Hunter,
Andi Kleen)
- Allow dumping the object files generated by llvm when processing
eBPF scriptlet events (Wang Nan)
- Add stackcollapse.py script to help generating flame graphs (Paolo
Bonzini)
- Add --ldlat option to 'perf mem' to specify load latency for loads
event (e.g. cpu/mem-loads/ ) (Jiri Olsa)
- Tooling support for Intel TopDown counters, recently added to the
kernel (Andi Kleen)"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (303 commits)
perf tests: Add is_printable_array test
perf tools: Make is_printable_array global
perf script python: Fix string vs byte array resolving
perf probe: Warn unmatched function filter correctly
perf cpu_map: Add more helpers
perf stat: Balance opening and reading events
tools: Copy linux/{hash,poison}.h and check for drift
perf tools: Remove include/linux/list.h from perf's MANIFEST
tools: Copy the bitops files accessed from the kernel and check for drift
Remove: kernel unistd*h files from perf's MANIFEST, not used
perf tools: Remove tools/perf/util/include/linux/const.h
perf tools: Remove tools/perf/util/include/asm/byteorder.h
perf tools: Add missing linux/compiler.h include to perf-sys.h
perf jit: Remove some no-op error handling
perf jit: Add missing curly braces
objtool: Initialize variable to silence old compiler
objtool: Add -I$(srctree)/tools/arch/$(ARCH)/include/uapi
perf record: Add --tail-synthesize option
perf session: Don't warn about out of order event if write_backward is used
perf tools: Enable overwrite settings
...
Linus Torvalds