linux/lib/Kconfig.debug, branch v5.8

kconfig: unify cc-option and as-option

2020-06-17T01:38:42Z

cc-option and as-option are almost the same; both pass the flag to $(CC). The main difference is the cc-option stops before the assemble stage (-S option) whereas as-option stops after (-c option). I chose -S because it is slightly faster, but $(cc-option,-gz=zlib) returns a wrong result (https://lkml.org/lkml/2020/6/9/1529). It has been fixed by commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection"), but the assembler should always be invoked for more reliable compiler option tests. However, you cannot simply replace -S with -c because the following code in lib/Kconfig.debug would break: depends on $(cc-option,-gsplit-dwarf) The combination of -c and -gsplit-dwarf does not accept /dev/null as output. $ cat /dev/null | gcc -gsplit-dwarf -S -x c - -o /dev/null $ echo $? 0 $ cat /dev/null | gcc -gsplit-dwarf -c -x c - -o /dev/null objcopy: Warning: '/dev/null' is not an ordinary file $ echo $? 1 $ cat /dev/null | gcc -gsplit-dwarf -c -x c - -o tmp.o $ echo $? 0 There is another flag that creates an separate file based on the object file path: $ cat /dev/null | gcc -ftest-coverage -c -x c - -o /dev/null :1: error: cannot open /dev/null.gcno So, we cannot use /dev/null to sink the output. Align the cc-option implementation with scripts/Kbuild.include. With -c option used in cc-option, as-option is unneeded. Signed-off-by: Masahiro Yamada Acked-by: Will Deacon

Makefile: Improve compressed debug info support detection

2020-06-15T01:26:42Z

Commit 10e68b02c861 ("Makefile: support compressed debug info") added support for compressed debug sections. Support is detected by checking - does the compiler support -gz=zlib - does the assembler support --compressed-debug-sections=zlib - does the linker support --compressed-debug-sections=zlib However, the gcc driver's support for this option is somewhat convoluted. The driver's builtin specs are set based on the version of binutils that it was configured with. It reports an error if the configure-time linker/assembler (i.e., not necessarily the actual assembler that will be run) do not support the option, but only if the assembler (or linker) is actually invoked when -gz=zlib is passed. The cc-option check in scripts/Kconfig.include does not invoke the assembler, so the gcc driver reports success even if it does not support the option being passed to the assembler. Because the as-option check passes the option directly to the assembler via -Wa,--compressed-debug-sections=zlib, the gcc driver does not see this option and will never report an error. Combined with an installed version of binutils that is more recent than the one the compiler was built with, it is possible for all three tests to succeed, yet an actual compilation with -gz=zlib to fail. Moreover, it is unnecessary to explicitly pass --compressed-debug-sections=zlib to the assembler via -Wa, since the driver will do that automatically when it supports -gz=zlib. Convert the as-option to just -gz=zlib, simplifying it as well as performing a better test of the gcc driver's capabilities. Reported-by: kernel test robot Signed-off-by: Arvind Sankar Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada

Merge tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2020-06-13T20:29:16Z

Pull more Kbuild updates from Masahiro Yamada: - fix build rules in binderfs sample - fix build errors when Kbuild recurses to the top Makefile - covert '---help---' in Kconfig to 'help' * tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: treewide: replace '---help---' in Kconfig files with 'help' kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables samples: binderfs: really compile this sample and fix build issues

treewide: replace '---help---' in Kconfig files with 'help'

2020-06-13T16:57:21Z

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over '---help---'"), the number of '---help---' has been gradually decreasing, but there are still more than 2400 instances. This commit finishes the conversion. While I touched the lines, I also fixed the indentation. There are a variety of indentation styles found. a) 4 spaces + '---help---' b) 7 spaces + '---help---' c) 8 spaces + '---help---' d) 1 space + 1 tab + '---help---' e) 1 tab + '---help---' (correct indentation) f) 1 tab + 1 space + '---help---' g) 1 tab + 2 spaces + '---help---' In order to convert all of them to 1 tab + 'help', I ran the following commend: $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/' Signed-off-by: Masahiro Yamada

Merge tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-06-12T01:55:43Z

Pull the Kernel Concurrency Sanitizer from Thomas Gleixner: "The Kernel Concurrency Sanitizer (KCSAN) is a dynamic race detector, which relies on compile-time instrumentation, and uses a watchpoint-based sampling approach to detect races. The feature was under development for quite some time and has already found legitimate bugs. Unfortunately it comes with a limitation, which was only understood late in the development cycle: It requires an up to date CLANG-11 compiler CLANG-11 is not yet released (scheduled for June), but it's the only compiler today which handles the kernel requirements and especially the annotations of functions to exclude them from KCSAN instrumentation correctly. These annotations really need to work so that low level entry code and especially int3 text poke handling can be completely isolated. A detailed discussion of the requirements and compiler issues can be found here: https://lore.kernel.org/lkml/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com/ We came to the conclusion that trying to work around compiler limitations and bugs again would end up in a major trainwreck, so requiring a working compiler seemed to be the best choice. For Continous Integration purposes the compiler restriction is manageable and that's where most xxSAN reports come from. For a change this limitation might make GCC people actually look at their bugs. Some issues with CSAN in GCC are 7 years old and one has been 'fixed' 3 years ago with a half baken solution which 'solved' the reported issue but not the underlying problem. The KCSAN developers also ponder to use a GCC plugin to become independent, but that's not something which will show up in a few days. Blocking KCSAN until wide spread compiler support is available is not a really good alternative because the continuous growth of lockless optimizations in the kernel demands proper tooling support" * tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (76 commits) compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining compiler.h: Move function attributes to compiler_types.h compiler.h: Avoid nested statement expression in data_race() compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE() kcsan: Update Documentation to change supported compilers kcsan: Remove 'noinline' from __no_kcsan_or_inline kcsan: Pass option tsan-instrument-read-before-write to Clang kcsan: Support distinguishing volatile accesses kcsan: Restrict supported compilers kcsan: Avoid inserting __tsan_func_entry/exit if possible ubsan, kcsan: Don't combine sanitizer with kcov on clang objtool, kcsan: Add kcsan_disable_current() and kcsan_enable_current_nowarn() kcsan: Add __kcsan_{enable,disable}_current() variants checkpatch: Warn about data_race() without comment kcsan: Use GFP_ATOMIC under spin lock Improve KCSAN documentation a bit kcsan: Make reporting aware of KCSAN tests kcsan: Fix function matching in report kcsan: Change data_race() to no longer require marking racing accesses kcsan: Move kcsan_{disable,enable}_current() to kcsan-checks.h ...

Rebase locking/kcsan to locking/urgent

2020-06-11T18:02:46Z

Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner

lib: test get_count_order/long in test_bitops.c

2020-06-11T02:14:18Z

Add some tests for get_count_order/long in test_bitops.c. [akpm@linux-foundation.org: define local `i'] [akpm@linux-foundation.org: enhancement, warning fix, cleanup per Geert] [akpm@linux-foundation.org: fix loop bound, per Wei Yang] Signed-off-by: Wei Yang Signed-off-by: Andrew Morton Reviewed-by: Andy Shevchenko Cc: Christian Brauner Cc: Geert Uytterhoeven Link: http://lkml.kernel.org/r/20200602223728.32722-1-richard.weiyang@gmail.com Signed-off-by: Linus Torvalds

Merge tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2020-06-09T17:04:47Z

Pull Kunit updates from Shuah Khan: "This consists of: - Several config fragment fixes from Anders Roxell to improve test coverage. - Improvements to kunit run script to use defconfig as default and restructure the code for config/build/exec/parse from Vitor Massaru Iha and David Gow. - Miscellaneous documentation warn fix" * tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: security: apparmor: default KUNIT_* fragments to KUNIT_ALL_TESTS fs: ext4: default KUNIT_* fragments to KUNIT_ALL_TESTS drivers: base: default KUNIT_* fragments to KUNIT_ALL_TESTS lib: Kconfig.debug: default KUNIT_* fragments to KUNIT_ALL_TESTS kunit: default KUNIT_* fragments to KUNIT_ALL_TESTS kunit: Kconfig: enable a KUNIT_ALL_TESTS fragment kunit: Fix TabError, remove defconfig code and handle when there is no kunitconfig kunit: use KUnit defconfig by default kunit: use --build_dir=.kunit as default Documentation: test.h - fix warnings kunit: kunit_tool: Separate out config/build/exec/parse

dynamic_debug: add an option to enable dynamic debug for modules only

2020-06-08T18:05:56Z

Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG, CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic debug. With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic debug will be tied to them. This is useful for people who only want to enable dynamic debug for kernel modules without worrying about kernel image size and memory consumption is increasing too much. [orson.zhai@unisoc.com: v2] Link: http://lkml.kernel.org/r/1587408228-10861-1-git-send-email-orson.unisoc@gmail.com Signed-off-by: Orson Zhai Signed-off-by: Andrew Morton Acked-by: Greg Kroah-Hartman Acked-by: Petr Mladek Cc: Jonathan Corbet Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Jason Baron Cc: Randy Dunlap Link: http://lkml.kernel.org/r/1586521984-5890-1-git-send-email-orson.unisoc@gmail.com Signed-off-by: Linus Torvalds

Merge tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2020-06-06T19:00:25Z

Pull Kbuild updates from Masahiro Yamada: - fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32 - ensure to rebuild all objects when the compiler is upgraded - exclude system headers from dependency tracking and fixdep processing - fix potential bit-size mismatch between the kernel and BPF user-mode helper - add the new syntax 'userprogs' to build user-space programs for the target architecture (the same arch as the kernel) - compile user-space sample code under samples/ for the target arch instead of the host arch - make headers_install fail if a CONFIG option is leaked to user-space - sanitize the output format of scripts/checkstack.pl - handle ARM 'push' instruction in scripts/checkstack.pl - error out before modpost if a module name conflict is found - error out when multiple directories are passed to M= because this feature is broken for a long time - add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info - a lot of cleanups of modpost - dump vmlinux symbols out into vmlinux.symvers, and reuse it in the second pass of modpost - do not run the second pass of modpost if nothing in modules is updated - install modules.builtin(.modinfo) by 'make install' as well as by 'make modules_install' because it is useful even when CONFIG_MODULES=n - add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ to allow users to use alternatives such as pigz, pbzip2, etc. * tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (96 commits) kbuild: add variables for compression tools Makefile: install modules.builtin even if CONFIG_MODULES=n mksysmap: Fix the mismatch of '.L' symbols in System.map kbuild: doc: rename LDFLAGS to KBUILD_LDFLAGS modpost: change elf_info->size to size_t modpost: remove is_vmlinux() helper modpost: strip .o from modname before calling new_module() modpost: set have_vmlinux in new_module() modpost: remove mod->skip struct member modpost: add mod->is_vmlinux struct member modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}() modpost: remove mod->is_dot_o struct member modpost: move -d option in scripts/Makefile.modpost modpost: remove -s option modpost: remove get_next_text() and make {grab,release_}file static modpost: use read_text_file() and get_line() for reading text files modpost: avoid false-positive file open error modpost: fix potential mmap'ed file overrun in get_src_version() modpost: add read_text_file() and get_line() helpers modpost: do not call get_modinfo() for vmlinux(.o) ...