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2015-02-13kasan: add kernel address sanitizer infrastructureAndrey Ryabinin
Kernel Address sanitizer (KASan) is a dynamic memory error detector. It provides fast and comprehensive solution for finding use-after-free and out-of-bounds bugs. KASAN uses compile-time instrumentation for checking every memory access, therefore GCC > v4.9.2 required. v4.9.2 almost works, but has issues with putting symbol aliases into the wrong section, which breaks kasan instrumentation of globals. This patch only adds infrastructure for kernel address sanitizer. It's not available for use yet. The idea and some code was borrowed from [1]. Basic idea: The main idea of KASAN is to use shadow memory to record whether each byte of memory is safe to access or not, and use compiler's instrumentation to check the shadow memory on each memory access. Address sanitizer uses 1/8 of the memory addressable in kernel for shadow memory and uses direct mapping with a scale and offset to translate a memory address to its corresponding shadow address. Here is function to translate address to corresponding shadow address: unsigned long kasan_mem_to_shadow(unsigned long addr) { return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET; } where KASAN_SHADOW_SCALE_SHIFT = 3. So for every 8 bytes there is one corresponding byte of shadow memory. The following encoding used for each shadow byte: 0 means that all 8 bytes of the corresponding memory region are valid for access; k (1 <= k <= 7) means that the first k bytes are valid for access, and other (8 - k) bytes are not; Any negative value indicates that the entire 8-bytes are inaccessible. Different negative values used to distinguish between different kinds of inaccessible memory (redzones, freed memory) (see mm/kasan/kasan.h). To be able to detect accesses to bad memory we need a special compiler. Such compiler inserts a specific function calls (__asan_load*(addr), __asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16. These functions check whether memory region is valid to access or not by checking corresponding shadow memory. If access is not valid an error printed. Historical background of the address sanitizer from Dmitry Vyukov: "We've developed the set of tools, AddressSanitizer (Asan), ThreadSanitizer and MemorySanitizer, for user space. We actively use them for testing inside of Google (continuous testing, fuzzing, running prod services). To date the tools have found more than 10'000 scary bugs in Chromium, Google internal codebase and various open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and lots of others): [2] [3] [4]. The tools are part of both gcc and clang compilers. We have not yet done massive testing under the Kernel AddressSanitizer (it's kind of chicken and egg problem, you need it to be upstream to start applying it extensively). To date it has found about 50 bugs. Bugs that we've found in upstream kernel are listed in [5]. We've also found ~20 bugs in out internal version of the kernel. Also people from Samsung and Oracle have found some. [...] As others noted, the main feature of AddressSanitizer is its performance due to inline compiler instrumentation and simple linear shadow memory. User-space Asan has ~2x slowdown on computational programs and ~2x memory consumption increase. Taking into account that kernel usually consumes only small fraction of CPU and memory when running real user-space programs, I would expect that kernel Asan will have ~10-30% slowdown and similar memory consumption increase (when we finish all tuning). I agree that Asan can well replace kmemcheck. We have plans to start working on Kernel MemorySanitizer that finds uses of unitialized memory. Asan+Msan will provide feature-parity with kmemcheck. As others noted, Asan will unlikely replace debug slab and pagealloc that can be enabled at runtime. Asan uses compiler instrumentation, so even if it is disabled, it still incurs visible overheads. Asan technology is easily portable to other architectures. Compiler instrumentation is fully portable. Runtime has some arch-dependent parts like shadow mapping and atomic operation interception. They are relatively easy to port." Comparison with other debugging features: ======================================== KMEMCHECK: - KASan can do almost everything that kmemcheck can. KASan uses compile-time instrumentation, which makes it significantly faster than kmemcheck. The only advantage of kmemcheck over KASan is detection of uninitialized memory reads. Some brief performance testing showed that kasan could be x500-x600 times faster than kmemcheck: $ netperf -l 30 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec no debug: 87380 16384 16384 30.00 41624.72 kasan inline: 87380 16384 16384 30.00 12870.54 kasan outline: 87380 16384 16384 30.00 10586.39 kmemcheck: 87380 16384 16384 30.03 20.23 - Also kmemcheck couldn't work on several CPUs. It always sets number of CPUs to 1. KASan doesn't have such limitation. DEBUG_PAGEALLOC: - KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page granularity level, so it able to find more bugs. SLUB_DEBUG (poisoning, redzones): - SLUB_DEBUG has lower overhead than KASan. - SLUB_DEBUG in most cases are not able to detect bad reads, KASan able to detect both reads and writes. - In some cases (e.g. redzone overwritten) SLUB_DEBUG detect bugs only on allocation/freeing of object. KASan catch bugs right before it will happen, so we always know exact place of first bad read/write. [1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel [2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs [3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs [4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs [5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies Based on work by Andrey Konovalov. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Acked-by: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Martin Schwidefsky: - The remaining patches for the z13 machine support: kernel build option for z13, the cache synonym avoidance, SMT support, compare-and-delay for spinloops and the CES5S crypto adapater. - The ftrace support for function tracing with the gcc hotpatch option. This touches common code Makefiles, Steven is ok with the changes. - The hypfs file system gets an extension to access diagnose 0x0c data in user space for performance analysis for Linux running under z/VM. - The iucv hvc console gets wildcard spport for the user id filtering. - The cacheinfo code is converted to use the generic infrastructure. - Cleanup and bug fixes. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (42 commits) s390/process: free vx save area when releasing tasks s390/hypfs: Eliminate hypfs interval s390/hypfs: Add diagnose 0c support s390/cacheinfo: don't use smp_processor_id() in preemptible context s390/zcrypt: fixed domain scanning problem (again) s390/smp: increase maximum value of NR_CPUS to 512 s390/jump label: use different nop instruction s390/jump label: add sanity checks s390/mm: correct missing space when reporting user process faults s390/dasd: cleanup profiling s390/dasd: add locking for global_profile access s390/ftrace: hotpatch support for function tracing ftrace: let notrace function attribute disable hotpatching if necessary ftrace: allow architectures to specify ftrace compile options s390: reintroduce diag 44 calls for cpu_relax() s390/zcrypt: Add support for new crypto express (CEX5S) adapter. s390/zcrypt: Number of supported ap domains is not retrievable. s390/spinlock: add compare-and-delay to lock wait loops s390/tape: remove redundant if statement s390/hvc_iucv: add simple wildcard matches to the iucv allow filter ...
2015-02-08Linux 3.19v3.19Linus Torvalds
2015-02-01Linux 3.19-rc7v3.19-rc7Linus Torvalds
2015-01-29ftrace: allow architectures to specify ftrace compile optionsHeiko Carstens
If the kernel is compiled with function tracer support the -pg compile option is passed to gcc to generate extra code into the prologue of each function. This patch replaces the "open-coded" -pg compile flag with a CC_FLAGS_FTRACE makefile variable which architectures can override if a different option should be used for code generation. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-01-25Linux 3.19-rc6v3.19-rc6Linus Torvalds
2015-01-18Linux 3.19-rc5v3.19-rc5Linus Torvalds
2015-01-11linux 3.19-rc4v3.19-rc4Linus Torvalds
2015-01-08Makefile: include arch/*/include/generated/uapi before .../generatedMichal Marek
The introduction of the uapi directories in v3.7-rc1 moved some of the generated headers from arch/*/include/generated to the uapi directory, keeping the #include directives intact. This creates a problem when bisecting, because the unversioned files are not cleaned automatically by git and the compiler might include stale headers as a result. Instead of cleaning them in the Makefiles, promote arch/*/include/generated/uapi in the search path. Under normal circumstances, there is no overlap between this uapi subdirectory and its parent, so the include choices remain the same. We keep arch/*/include/generated/uapi in the USERINCLUDE variable so that it is usable standalone. Note that we cannot completely swap the order of the uapi and kernel-only directories, since the headers in include/uapi/asm-generic are meant to be wrapped by their include/asm-generic counterparts when building kernel code. Reported-by: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Reported-by: David Drysdale <dmd@lurklurk.org> Signed-off-by: Michal Marek <mmarek@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-01-05Linux 3.19-rc3v3.19-rc3Linus Torvalds
2014-12-28Linux 3.19-rc2v3.19-rc2Linus Torvalds
2014-12-20Linux 3.19-rc1v3.19-rc1Linus Torvalds
2014-12-20Merge branch 'kbuild' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild updates from Michal Marek: "Here are the kbuild changes for v3.19-rc1: - Cleanups and deduplication in the main Makefile and scripts/Makefile.* - Sort the output of *config targets in make help - Old <linux/version.h> is always removed to avoid a surprise during bisecting - Warning fix in kconfig" * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: remove redundant -rR flag of hdr-inst kbuild: Fix make help-<board series> on powerpc kbuild: Automatically remove stale <linux/version.h> file kconfig: Fix warning "‘jump’ may be used uninitialized" Makefile: sort list of defconfig targets in make help output kbuild: Remove duplicate $(cmd) definition in Makefile.clean kbuild: collect shorthands into scripts/Kbuild.include
2014-12-07Linux 3.18v3.18Linus Torvalds
2014-11-30Linux 3.18-rc7v3.18-rc7Linus Torvalds
2014-11-28kbuild: Fix make help-<board series> on powerpcMichal Marek
make ARCH=powerpc help-<board series> should not require a cofigured source tree. Also, sort the boards in the output. Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-11-28kbuild: Automatically remove stale <linux/version.h> fileMichal Marek
In 3.7, the file moved from include/linux/ to include/generated/uapi/linux/. The path in the #include directive remained the same for compatibility reasons, but this created a problem when bisecting. Commit 9c8cdb71 (kbuild: unconditionally clobber include/linux/version.h on distclean) fixes this, provided the user does make distclean between builds. Better not rely on the user and delete the stale file each time make is invoked. Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-11-28Makefile: sort list of defconfig targets in make help outputKonstantin Khlebnikov
Without sorting this list is completely unreadable for ARCH=arm. Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-11-26kbuild: collect shorthands into scripts/Kbuild.includeMasahiro Yamada
The shorthand "clean" is defined in both the top Makefile and scripts/Makefile.clean. Likewise, the "hdr-inst" is defined in both the top Makefile and scripts/Makefile.headersinst. To reduce code duplication, this commit collects them into scripts/Kbuild.include like the "build" and "modbuiltin" shorthands. It requires scripts/Makefile.clean to include scripts/Kbuild.include, but its impact on the performance of "make clean" should be negligible. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-11-23Linux 3.18-rc6v3.18-rc6Linus Torvalds
2014-11-16Linux 3.18-rc5v3.18-rc5Linus Torvalds
2014-11-15kernel: use the gnu89 standard explicitlyKirill A. Shutemov
Sasha Levin reports: "gcc5 changes the default standard to c11, which makes kernel build unhappy Explicitly define the kernel standard to be gnu89 which should keep everything working exactly like it was before gcc5" There are multiple small issues with the new default, but the biggest issue seems to be that the old - and very useful - GNU extension to allow a cast in front of an initializer has gone away. Patch updated by Kirill: "I'm pretty sure all gcc versions you can build kernel with supports -std=gnu89. cc-option is redunrant. We also need to adjust HOSTCFLAGS otherwise allmodconfig fails for me" Note by Andrew Pinski: "Yes it was reported and both problems relating to this extension has been added to gnu99 and gnu11. Though there are other issues with the kernel dealing with extern inline have different semantics between gnu89 and gnu99/11" End result: we may be able to move up to a newer stdc model eventually, but right now the newer models have some annoying deficiencies, so the traditional "gnu89" model ends up being the preferred one. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Singed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-09Linux 3.18-rc4v3.18-rc4Linus Torvalds
2014-11-02Linux 3.18-rc3v3.18-rc3Linus Torvalds
2014-10-26Linux 3.18-rc2v3.18-rc2Linus Torvalds
2014-10-19Linux 3.18-rc1v3.18-rc1Linus Torvalds
2014-10-14Merge branch 'kbuild' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild changes from Michal Marek: - fix for handling dependencies of *-objs targets by Masahiro Yamada - lots of cleanups in the kbuild machinery, also by Masahiro - fixes for the kconfig build to use an UTF-8 capable ncurses library if possible and to build on not-so-standard installs - some more minor fixes * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: Do not reference *-n variables in the Makefile kbuild: simplify build, clean, modbuiltin shorthands kbuild: arm: Do not define "comma" twice kbuild: remove obj-n and lib-n handling kbuild: remove unnecessary variable initializaions kbuild: remove unnecessary "obj- := dummy.o" trick kbuild: handle C=... and M=... after entering into build directory kbuild: use $(Q) for sub-make target kbuild: fake the "Entering directory ..." message more simply kconfig/lxdialog: get ncurses CFLAGS with pkg-config kconfig: nconfig: fix multi-byte UTF handling kconfig: lxdialog: fix spelling kbuild: Make scripts executable kbuild: remove redundant clean-files from scripts/kconfig/Makefile kbuild: refactor script/kconfig/Makefile kbuild: handle the dependency of multi-objs hostprogs appropriately kbuild: handle multi-objs dependency appropriately
2014-10-07Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/doc Pull documentation updates from Jiri Kosina: "Updates to kernel documentation. I took this over (hopefully temporarily) from Randy who was not willing to maintain it any longer. This pile mostly is a relay of queue that Randy already had in his tree" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/doc: Documentation: fix broken v4l-utils URL Documentation: update include path for mpssd Documentation: correct parameter error for dma_mapping_error MAINTAINERS: update location of linux-doc tree Documentation: remove networking/.gitignore tools: add more endian.h macros Make Documenation depend on headers_install Docs: this_cpu_ops: remove redundant add forms Documentation: disable vdso_test to avoid breakage with old glibc Documentation: update vDSO makefile to build portable examples Documentation: update .gitignore files Documentation: support glibc versions without htole macros v4l2-pci-skeleton: Only build if PCI is available Documentation: fix misc. warnings Documentation: make functions static to avoid prototype warnings Documentation: add makefiles for more targets Documentation: use subdir-y to avoid unnecessary built-in.o files
2014-10-07Merge tag 'modules-next-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull module update from Rusty Russell: "Nothing major: support for compressing modules, and auto-tainting params. PS. My virtio-next tree is empty: DaveM took the patches I had. There might be a virtio-rng starvation fix, but so far it's a bit voodoo so I will get to that in the next two days or it will wait" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: moduleparam: Resolve missing-field-initializer warning kbuild: handle module compression while running 'make modules_install'. modinst: wrap long lines in order to enhance cmd_modules_install modsign: lookup lines ending in .ko in .mod files modpost: simplify file name generation of *.mod.c files modpost: reduce visibility of symbols and constify r/o arrays param: check for tainting before calling set op. drm/i915: taint the kernel if unsafe module parameters are set module: add module_param_unsafe and module_param_named_unsafe module: make it possible to have unsafe, tainting module params module: rename KERNEL_PARAM_FL_NOARG to avoid confusion
2014-10-05Linux 3.17v3.17Linus Torvalds
2014-10-02kbuild: Do not reference *-n variables in the MakefileMichal Marek
Kconfig options are either 'y', 'm', or undefined. Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-10-02kbuild: simplify build, clean, modbuiltin shorthandsMasahiro Yamada
$(if $(KBUILD_SRC),$(srctree)/) was a useful strategy to omit a long absolute path for in-source-tree build prior to commit 890676c65d699db3ad82e7dddd0cf8fb449031af (kbuild: Use relative path when building in the source tree). Now $(srctree) is "." when building in the source tree. It would not be annoying to add "$(srctree)/" all the time. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-10-01kbuild: handle C=... and M=... after entering into build directoryMasahiro Yamada
This commit avoids processing C=... and M=... twice when O=... is also given. Besides, we can also remove KBUILD_EXTMOD="$(KBUILD_EXTMOD)" in the sub-make target. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Acked-by: Peter Foley <pefoley2@pefoley.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-10-01kbuild: use $(Q) for sub-make targetMasahiro Yamada
Since commit 066b7ed9558087a7957a1128f27d7a3462ff117f (kbuild: Do not print the build directory with make -s), "Q" is defined above the sub-make target. This commit takes advantage of that and replaces "$(if $(KBUILD_VERBOSE:1=),@)" with "$(Q)". Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Acked-by: Peter Foley <pefoley2@pefoley.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-10-01kbuild: fake the "Entering directory ..." message more simplyMasahiro Yamada
Commit c2e28dc975ea87feed84415006ae143424912ac7 (kbuild: Print the name of the build directory) added a gimmick to show the "Entering directory ...". Instead of echoing the hard-coded message (that is, we need to know the exact message), moving --no-print-directory would be easier. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Acked-by: Peter Foley <pefoley2@pefoley.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-09-28Linux 3.17-rc7v3.17-rc7Linus Torvalds
2014-09-26Make Documenation depend on headers_installPeter Foley
Cc: rdunlap@infradead.org Cc: linux-doc@vger.kernel.org Cc: sudeep.dutt@intel.com Cc: nikhil.rao@intel.com Cc: ashutosh.dixit@intel.com Cc: akpm@linux-foundation.org Cc: gregkh@linuxfoundation.org Signed-off-by: Peter Foley <pefoley2@pefoley.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-21Linux 3.17-rc6v3.17-rc6Linus Torvalds
2014-09-14Linux 3.17-rc5v3.17-rc5Linus Torvalds
2014-09-07Linux 3.17-rc4v3.17-rc4Linus Torvalds
2014-08-31Linux 3.17-rc3v3.17-rc3Linus Torvalds
2014-08-27kbuild: handle module compression while running 'make modules_install'.Bertrand Jacquin
Since module-init-tools (gzip) and kmod (gzip and xz) support compressed modules, it could be useful to include a support for compressing modules right after having them installed. Doing this in kbuild instead of per distro can permit to make this kind of usage more generic. This patch add a Kconfig entry to "Enable loadable module support" menu and let you choose to compress using gzip (default) or xz. Both gzip and xz does not used any extra -[1-9] option since Andi Kleen and Rusty Russell prove no gain is made using them. gzip is called with -n argument to avoid storing original filename inside compressed file, that way we can save some more bytes. On a v3.16 kernel, 'make allmodconfig' generated 4680 modules for a total of 378MB (no strip, no sign, no compress), the following table shows observed disk space gain based on the allmodconfig .config : | time | +-------------+-----------------+ | manual .ko | make | size | percent | compression | modules_install | | gain +-------------+-----------------+------+-------- - | | 18.61s | 378M | GZIP | 3m16s | 3m37s | 102M | 73.41% XZ | 5m22s | 5m39s | 77M | 79.83% The gain for restricted environnement seems to be interesting while uncompress can be time consuming but happens only while loading a module, that is generally done only once. This is fully compatible with signed modules while the signed module is compressed. module-init-tools or kmod handles decompression and provide to other layer the uncompressed but signed payload. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Bertrand Jacquin <beber@meleeweb.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-08-25Linux 3.17-rc2v3.17-rc2Linus Torvalds
2014-08-16Linux 3.17-rc1v3.17-rc1Linus Torvalds
2014-08-14Merge branch 'misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull misc kbuild updates from Michal Marek: "This is the non-critical part of kbuild for 3.17-rc1: - make help hint to use make -s with make kernelrelease et al. - moved a kbuild document to Documentation/kbuild where it belongs - four new Coccinelle scripts, one dropped and one fixed - new make kselftest target to run various tests on the kernel" * 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: kselftest - new make target to build and run kernel selftests Coccinelle: Script to replace if and BUG with BUG_ON Coccinelle: Script to detect incorrect argument to sizeof Coccinelle: Script to use ARRAY_SIZE instead of division of two sizeofs Coccinelle: Script to detect cast after memory allocation coccinelle/null: solve parse error Documentation: headers_install.txt is part of kbuild kbuild: make -s should be used with kernelrelease/kernelversion/image_name
2014-08-14Merge branch 'kbuild' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild updates from Michal Marek: - make clean also considers $(extra-m) and $(extra-) to be consistent - cleanup and fixes in scripts/Makefile.host - allow to override the name of the Python 2 executable with make PYTHON=... (only needed for ia64 in practice) - option to split debugingo into *.dwo files to save disk space if the compiler supports it (CONFIG_DEBUG_INFO_SPLIT) - option to use dwarf4 debuginfo if the compiler supports it (CONFIG_DEBUG_INFO_DWARF4) - fix for disabling certain warnings with clang - fix for unneeded rebuild with dash when a command contains backslashes * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: Fix handling of backslashes in *.cmd files kbuild, LLVMLinux: Supress warnings unless W=1-3 Kbuild: Add a option to enable dwarf4 v2 kbuild: Support split debug info v4 kbuild: allow to override Python command name kbuild: clean-up and bug fix of scripts/Makefile.host kbuild: clean up scripts/Makefile.host kbuild: drop shared library support from Makefile.host kbuild: fix a bug of C++ host program handling kbuild: fix a typo in scripts/Makefile.host scripts/Makefile.clean: clean also $(extra-m) and $(extra-)
2014-08-07kbuild: kselftest - new make target to build and run kernel selftestsShuah Khan
Add a new make target "kselftest" to enable kernel testing. This new target builds and runs kernel selftests. Running as root is recommended for a complete test run as some tests don't run when run by non-root user. Build, install, and boot kernel before running kselftest on it. Signed-off-by: Shuah Khan <shuah.kh@samsung.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-08-06./Makefile: tell gcc optimizer to never introduce new data racesJiri Kosina
We have been chasing a memory corruption bug, which turned out to be caused by very old gcc (4.3.4), which happily turned conditional load into a non-conditional one, and that broke correctness (the condition was met only if lock was held) and corrupted memory. This particular problem with that particular code did not happen when never gccs were used. I've brought this up with our gcc folks, as I wanted to make sure that this can't really happen again, and it turns out it actually can. Quoting Martin Jambor <mjambor@suse.cz>: "More current GCCs are more careful when it comes to replacing a conditional load with a non-conditional one, most notably they check that a store happens in each iteration of _a_ loop but they assume loops are executed. They also perform a simple check whether the store cannot trap which currently passes only for non-const variables. A simple testcase demonstrating it on an x86_64 is for example the following: $ cat cond_store.c int g_1 = 1; int g_2[1024] __attribute__((section ("safe_section"), aligned (4096))); int c = 4; int __attribute__ ((noinline)) foo (void) { int l; for (l = 0; (l != 4); l++) { if (g_1) return l; for (g_2[0] = 0; (g_2[0] >= 26); ++g_2[0]) ; } return 2; } int main (int argc, char* argv[]) { if (mprotect (g_2, sizeof(g_2), PROT_READ) == -1) { int e = errno; error (e, e, "mprotect error %i", e); } foo (); __builtin_printf("OK\n"); return 0; } /* EOF */ $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=0 $ ./a.out OK $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=1 $ ./a.out Segmentation fault The testcase fails the same at least with 4.9, 4.8 and 4.7. Therefore I would suggest building kernels with this parameter set to zero. I also agree with Jikos that the default should be changed for -O2. I have run most of the SPEC 2k6 CPU benchmarks (gamess and dealII failed, at -O2, not sure why) compiled with and without this option and did not see any real difference between respective run-times" Hopefully the default will be changed in newer gccs, but let's force it for kernel builds so that we are on a safe side even when older gcc are used. The code in question was out-of-tree printk-in-NMI (yeah, surprise suprise, once again) patch written by Petr Mladek, let me quote his comment from our internal bugzilla: "I have spent few days investigating inconsistent state of kernel ring buffer. It went out that it was caused by speculative store generated by gcc-4.3.4. The problem is in assembly generated for make_free_space(). The functions is called the following way: + vprintk_emit(); + log = MAIN_LOG; // with logbuf_lock or log = NMI_LOG; // with nmi_logbuf_lock cont_add(log, ...); + cont_flush(log, ...); + log_store(log, ...); + log_make_free_space(log, ...); If called with log = NMI_LOG then only nmi_log_* global variables are safe to modify but the generated code does store also into (main_)log_* global variables: <log_make_free_space>: 55 push %rbp 89 f6 mov %esi,%esi 48 8b 05 03 99 51 01 mov 0x1519903(%rip),%rax # ffffffff82620868 <nmi_log_next_id> 44 8b 1d ec 98 51 01 mov 0x15198ec(%rip),%r11d # ffffffff82620858 <log_next_idx> 8b 35 36 60 14 01 mov 0x1146036(%rip),%esi # ffffffff8224cfa8 <log_buf_len> 44 8b 35 33 60 14 01 mov 0x1146033(%rip),%r14d # ffffffff8224cfac <nmi_log_buf_len> 4c 8b 2d d0 98 51 01 mov 0x15198d0(%rip),%r13 # ffffffff82620850 <log_next_seq> 4c 8b 25 11 61 14 01 mov 0x1146111(%rip),%r12 # ffffffff8224d098 <log_buf> 49 89 c2 mov %rax,%r10 48 21 c2 and %rax,%rdx 48 8b 1d 0c 99 55 01 mov 0x155990c(%rip),%rbx # ffffffff826608a0 <nmi_log_buf> 49 c1 ea 20 shr $0x20,%r10 48 89 55 d0 mov %rdx,-0x30(%rbp) 44 29 de sub %r11d,%esi 45 29 d6 sub %r10d,%r14d 4c 8b 0d 97 98 51 01 mov 0x1519897(%rip),%r9 # ffffffff82620840 <log_first_seq> eb 7e jmp ffffffff81107029 <log_make_free_space+0xe9> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 e8 mov %r13,%rax 4c 89 ca mov %r9,%rdx 74 0a je ffffffff8110703d <log_make_free_space+0xfd> 8b 15 27 98 51 01 mov 0x1519827(%rip),%edx # ffffffff82620860 <nmi_log_first_id> 48 8b 45 d0 mov -0x30(%rbp),%rax 48 39 c2 cmp %rax,%rdx # end of loop 0f 84 da 00 00 00 je ffffffff81107120 <log_make_free_space+0x1e0> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 0d 17 97 51 01 mov %r9,0x1519717(%rip) # ffffffff82620840 <log_first_seq> ^^^^^^^^^^^^^^^^^^^^^^^^^^ KABOOOM 74 35 je ffffffff81107160 <log_make_free_space+0x220> It stores log_first_seq when edi == NMI_LOG. This instructions are used also when edi == MAIN_LOG but the store is done speculatively before the condition is decided. It is unsafe because we do not have "logbuf_lock" in NMI context and some other process migh modify "log_first_seq" in parallel" I believe that the best course of action is both - building kernel (and anything multi-threaded, I guess) with that optimization turned off - persuade gcc folks to change the default for future releases Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Martin Jambor <mjambor@suse.cz> Cc: Petr Mladek <pmladek@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Marek Polacek <polacek@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Steven Noonan <steven@uplinklabs.net> Cc: Richard Biener <richard.guenther@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06./Makefile: explain stack-protector-strong CONFIG logicKees Cook
This adds a hopefully helpful comment above the (seemingly weird) compiler flag selection logic. Signed-off-by: Kees Cook <keescook@chromium.org> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-05kbuild, LLVMLinux: Supress warnings unless W=1-3Behan Webster
clang has more warnings enabled by default. Turn them off unless W is set. This patch fixes a logic bug where warnings in clang were disabled when W was set. Signed-off-by: Behan Webster <behanw@converseincode.com> Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de> Signed-off-by: Mark Charlebois <charlebm@gmail.com> Cc: bp@alien8.de Signed-off-by: Michal Marek <mmarek@suse.cz>
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