kernel/linux.git - Linux kernel stable tree (mirror)

Age	Commit message (Collapse)	Author	Files	Lines
2023-03-17	scripts: handle BrokenPipeError for python scripts	Masahiro Yamada	1	-7/+14
	[ Upstream commit 87c7ee67deb7fce9951a5f9d80641138694aad17 ] In the follow-up of commit fb3041d61f68 ("kbuild: fix SIGPIPE error message for AR=gcc-ar and AR=llvm-ar"), Kees Cook pointed out that tools should _not_ catch their own SIGPIPEs [1] [2]. Based on his feedback, LLVM was fixed [3]. However, Python's default behavior is to show noisy bracktrace when SIGPIPE is sent. So, scripts written in Python are basically in the same situation as the buggy llvm tools. Example: $ make -s allnoconfig $ make -s allmodconfig $ scripts/diffconfig .config.old .config \| head -n1 -ALIX n Traceback (most recent call last): File "/home/masahiro/linux/scripts/diffconfig", line 132, in <module> main() File "/home/masahiro/linux/scripts/diffconfig", line 130, in main print_config("+", config, None, b[config]) File "/home/masahiro/linux/scripts/diffconfig", line 64, in print_config print("+%s %s" % (config, new_value)) BrokenPipeError: [Errno 32] Broken pipe Python documentation [4] notes how to make scripts die immediately and silently: """ Piping output of your program to tools like head(1) will cause a SIGPIPE signal to be sent to your process when the receiver of its standard output closes early. This results in an exception like BrokenPipeError: [Errno 32] Broken pipe. To handle this case, wrap your entry point to catch this exception as follows: import os import sys def main(): try: # simulate large output (your code replaces this loop) for x in range(10000): print("y") # flush output here to force SIGPIPE to be triggered # while inside this try block. sys.stdout.flush() except BrokenPipeError: # Python flushes standard streams on exit; redirect remaining output # to devnull to avoid another BrokenPipeError at shutdown devnull = os.open(os.devnull, os.O_WRONLY) os.dup2(devnull, sys.stdout.fileno()) sys.exit(1) # Python exits with error code 1 on EPIPE if __name__ == '__main__': main() Do not set SIGPIPE’s disposition to SIG_DFL in order to avoid BrokenPipeError. Doing that would cause your program to exit unexpectedly whenever any socket connection is interrupted while your program is still writing to it. """ Currently, tools/perf/scripts/python/intel-pt-events.py seems to be the only script that fixes the issue that way. tools/perf/scripts/python/compaction-times.py uses another approach signal.signal(signal.SIGPIPE, signal.SIG_DFL) but the Python documentation clearly says "Don't do it". I cannot fix all Python scripts since there are so many. I fixed some in the scripts/ directory. [1]: https://lore.kernel.org/all/202211161056.1B9611A@keescook/ [2]: https://github.com/llvm/llvm-project/issues/59037 [3]: https://github.com/llvm/llvm-project/commit/4787efa38066adb51e2c049499d25b3610c0877b [4]: https://docs.python.org/3/library/signal.html#note-on-sigpipe Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22	gen_compile_commands: fix missing 'sys' package	Kortan	1	-0/+1
	commit ec783c7cb2495c5a3b8ca10db8056d43c528f940 upstream. We need to import the 'sys' package since the script has called sys.exit() method. Fixes: 6ad7cbc01527 ("Makefile: Add clang-tidy and static analyzer support to makefile") Signed-off-by: Kortan <kortanzh@gmail.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-03	scripts/clang-tools: switch explicitly to Python 3	Masahiro Yamada	2	-2/+2
	commit 074075aea2ff72dade5231b4ee9f2ab9a055f1ec upstream. For the same reason as commit 51839e29cb59 ("scripts: switch explicitly to Python 3"), switch some more scripts, which I tested and confirmed working on Python 3. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-26	Makefile: Add clang-tidy and static analyzer support to makefile	Nathan Huckleberry	2	-0/+310
	This patch adds clang-tidy and the clang static-analyzer as make targets. The goal of this patch is to make static analysis tools usable and extendable by any developer or researcher who is familiar with basic c++. The current static analysis tools require intimate knowledge of the internal workings of the static analysis. Clang-tidy and the clang static analyzers expose an easy to use api and allow users unfamiliar with clang to write new checks with relative ease. ===Clang-tidy=== Clang-tidy is an easily extendable 'linter' that runs on the AST. Clang-tidy checks are easy to write and understand. A check consists of two parts, a matcher and a checker. The matcher is created using a domain specific language that acts on the AST (https://clang.llvm.org/docs/LibASTMatchersReference.html). When AST nodes are found by the matcher a callback is made to the checker. The checker can then execute additional checks and issue warnings. Here is an example clang-tidy check to report functions that have calls to local_irq_disable without calls to local_irq_enable and vice-versa. Functions flagged with __attribute((annotation("ignore_irq_balancing"))) are ignored for analysis. (https://reviews.llvm.org/D65828) ===Clang static analyzer=== The clang static analyzer is a more powerful static analysis tool that uses symbolic execution to find bugs. Currently there is a check that looks for potential security bugs from invalid uses of kmalloc and kfree. There are several more general purpose checks that are useful for the kernel. The clang static analyzer is well documented and designed to be extensible. (https://clang-analyzer.llvm.org/checker_dev_manual.html) (https://github.com/haoNoQ/clang-analyzer-guide/releases/download/v0.1/clang-analyzer-guide-v0.1.pdf) The main draw of the clang tools is how accessible they are. The clang documentation is very nice and these tools are built specifically to be easily extendable by any developer. They provide an accessible method of bug-finding and research to people who are not overly familiar with the kernel codebase. Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>