In the upcoming gcc7 release, the -fsanitize=kernel-address option at
first implied new -fsanitize-address-use-after-scope option. This would
cause link errors on older kernels because they don't have two new
functions required for use-after-scope support. Therefore, gcc7 changed
default to -fno-sanitize-address-use-after-scope.
Now the kernel has everything required for that feature since commit
828347f8f9 ("kasan: support use-after-scope detection"). So, to make it
work, we just have to enable use-after-scope in CFLAGS.
Link: http://lkml.kernel.org/r/1481207977-28654-1-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Every often used regex is better be compiled in Python.
Speedup is about ~9.8% (whee!)
$ perf stat -r 16 taskset -c 15 ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux >/dev/null
7.091202853 seconds time elapsed ( +- 0.15% )
+re.compile
6.397564973 seconds time elapsed ( +- 0.34% )
Link: http://lkml.kernel.org/r/20161119004417.GB1200@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
readlines() conses whole list before doing anything which is slower for
big object files. Use per line iterator.
Speed up is ~2% on "allyesconfig" type of kernel.
$ perf stat -r 16 taskset -c 15 ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux >/dev/null
...
Before: 7.247708646 seconds time elapsed ( +- 0.28% )
After: 7.091202853 seconds time elapsed ( +- 0.15% )
Link: http://lkml.kernel.org/r/20161119004143.GA1200@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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
Merge fixes for -Wmaybe-uninitialized from Arnd Bergmann:
"It took a while for some patches to make it into mainline through
maintainer trees, but the 28-patch series is now reduced to 10, with
one tiny patch added at the end.
Aside from patches that are no longer required, I did these changes
compared to version 1:
- Dropped "iio: maxim_thermocouple: detect invalid storage size in
read()", which is currently in linux-next as commit 32cb7d27e6.
This is the only remaining warning I see for a couple of corner
cases (kbuild bot reports it on blackfin, kernelci bot and arm-soc
bot both report it on arm64)
- Dropped "brcmfmac: avoid maybe-uninitialized warning in
brcmf_cfg80211_start_ap", which is currently in net/master merge
pending.
- Dropped two x86 patches, "x86: math-emu: possible uninitialized
variable use" and "x86: mark target address as output in 'insb'
asm" as they do not seem to trigger for a default build, and I got
no feedback on them. Both of these are ancient issues and seem
harmless, I will send them again to the x86 maintainers once the
rest is merged.
- Dropped "rbd: false-postive gcc-4.9 -Wmaybe-uninitialized" based on
feedback from Ilya Dryomov, who already has a different fix queued
up for v4.10. The kbuild bot reports this as a warning for xtensa.
- Replaced "crypto: aesni: avoid -Wmaybe-uninitialized warning" with
a simpler patch, this one always triggers but my first solution
would not be safe for linux-4.9 any more at this point. I'll follow
up with the larger patch as a cleanup for 4.10.
- Replaced "dib0700: fix nec repeat handling" with a better one,
contributed by Sean Young"
* -Wmaybe-uninitialized fixes:
Kbuild: enable -Wmaybe-uninitialized warnings by default
pcmcia: fix return value of soc_pcmcia_regulator_set
infiniband: shut up a maybe-uninitialized warning
crypto: aesni: shut up -Wmaybe-uninitialized warning
rc: print correct variable for z8f0811
dib0700: fix nec repeat handling
s390: pci: don't print uninitialized data for debugging
nios2: fix timer initcall return value
x86: apm: avoid uninitialized data
NFSv4.1: work around -Wmaybe-uninitialized warning
Kbuild: enable -Wmaybe-uninitialized warning for "make W=1"
Previously the warnings were added back at the W=1 level and above, this
now turns them on again by default, assuming that we have addressed all
warnings and again have a clean build for v4.10.
I found a number of new warnings in linux-next already and submitted
bugfixes for those. Hopefully they are caught by the 0day builder in
the future as soon as this patch is merged.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
The CRC code for asm exports grabs the preprocessed asm, finds the
___EXPORT_SYMBOL and turns those into EXPORT_SYMBOL in a C program
that can be preprocessed and parsed to create the CRC signatures from
the type.
The existing regex matching and replacement is too strict, and doesn't
deal well with whitespace among other things. The line
" EXPORT_SYMBOL(sym)" in a .S file would not match due to initial
whitespace, for example, which resulted in x86's ___preempt_schedule
failing to get CRCs.
Reported-by: Philip Müller <philm@manjaro.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Adding -no-PIE to the fstack protector check. -no-PIE was introduced
before -fstack-protector so there is no need for a runtime check.
Without it the build stops:
|Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong available but compiler is broken
due to -mcmodel=kernel + -fPIE if -fPIE is enabled by default.
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>
Allow architectures to create asm/asm-prototypes.h file that
provides C prototypes for exported asm functions, which enables
proper CRC versions to be generated for them.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
The stack frame size could grow too large when the plugin used long long
on 32-bit architectures when the given function had too many basic blocks.
The gcc warning was:
drivers/pci/hotplug/ibmphp_ebda.c: In function 'ibmphp_access_ebda':
drivers/pci/hotplug/ibmphp_ebda.c:409:1: warning: the frame size of 1108 bytes is larger than 1024 bytes [-Wframe-larger-than=]
This switches latent_entropy from u64 to unsigned long.
Thanks to PaX Team and Emese Revfy for the patch.
Signed-off-by: Kees Cook <keescook@chromium.org>
Pull gcc plugins update from Kees Cook:
"This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot
time as possible, hoping to capitalize on any possible variation in
CPU operation (due to runtime data differences, hardware differences,
SMP ordering, thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example
for how to manipulate kernel code using the gcc plugin internals"
* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
latent_entropy: Mark functions with __latent_entropy
gcc-plugins: Add latent_entropy plugin
Pull misc kbuild changes from Michal Marek:
"Just a few patches on the kbuild.git#misc branch this time:
- New Coccinelle patch by Nicholas Mc Guire
- Existing patch fixes by Julia Lawall
- Minor comment fix by Markus Elfring"
* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
Coccinelle: flag conditions with no effect
scripts/coccicheck: Update reference for the corresponding documentation
Coccinelle: pm_runtime: ensure relevance of pm_runtime reports
Coccinelle: limit memdup_user transformation to GFP_KERNEL case
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
...
