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For a user mode library to avoid generating SIGPIPE signals (e.g. because this behaviour is not portable across operating systems) is cumbersome. It is generally bad form to change the process-wide signal mask in a library, so a local solution is needed instead. For I/O performed directly using system calls (synchronous or readiness based asynchronous) this currently involves applying a thread-specific signal mask before the operation and reverting it afterwards. This can be avoided when it is known that the file descriptor refers to neither a pipe nor a socket, but a conservative implementation must always apply the mask. This incurs the cost of two additional system calls. In the case of sockets, the existing MSG_NOSIGNAL flag can be used with send. For asynchronous I/O performed using io_uring, currently the only option (apart from MSG_NOSIGNAL for sockets), is to mask SIGPIPE entirely in the call to io_uring_enter. Thankfully io_uring_enter takes a signal mask, so only a single syscall is needed. However, copying the signal mask on every call incurs a non-zero performance penalty. Furthermore, this mask applies to all completions, meaning that if the non-signaling behaviour is desired only for some subset of operations, the desired signals must be raised manually from user-mode depending on the completed operation. Add RWF_NOSIGNAL flag for pwritev2. This flag prevents the SIGPIPE signal from being raised when writing on disconnected pipes or sockets. The flag is handled directly by the pipe filesystem and converted to the existing MSG_NOSIGNAL flag for sockets. Signed-off-by: Lauri Vasama <git@vasama.org> Link: https://lore.kernel.org/20250827133901.1820771-1-git@vasama.org Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org> |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.