linux/scripts, branch v4.9

kbuild: make sure autoksyms.h exists early

2016-12-01T18:19:22Z

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 Tested-by: Prarit Bhargava Tested-by: Jarod Wilson Signed-off-by: Linus Torvalds

Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

2016-11-19T00:45:21Z

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 branch 'maybe-uninitialized' (patches from Arnd)

2016-11-11T18:03:01Z

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 32cb7d27e65d. 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"

Kbuild: enable -Wmaybe-uninitialized warnings by default

2016-11-11T16:45:08Z

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 Signed-off-by: Linus Torvalds

Kbuild: enable -Wmaybe-uninitialized warning for "make W=1"

2016-11-11T16:45:08Z

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 e74fc973b6e5 ("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 877417e6ffb9 ("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 6e8d666e9253 ("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 Signed-off-by: Linus Torvalds

scripts/bloat-o-meter: fix SIGPIPE

2016-11-11T16:12:37Z

Fix piping output to a program which quickly exits (read: head -n1) $ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux | head -n1 add/remove: 0/0 grow/shrink: 9/60 up/down: 124/-305 (-181) close failed in file object destructor: sys.excepthook is missing lost sys.stderr Link: http://lkml.kernel.org/r/20161028204618.GA29923@avx2 Signed-off-by: Alexey Dobriyan Cc: Matt Mackall Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL

2016-11-09T21:29:53Z

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 Signed-off-by: Nicholas Piggin Signed-off-by: Michal Marek

scripts/has-stack-protector: add -fno-PIE

2016-11-09T21:28:05Z

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 Signed-off-by: Michal Marek

kbuild: modversions for EXPORT_SYMBOL() for asm

2016-11-01T15:20:17Z

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 Signed-off-by: Michal Marek

latent_entropy: Fix wrong gcc code generation with 64 bit variables

2016-10-31T18:30:41Z

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