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Rob Norris
ede715d1e4
All of our thread entry functions have this signature:
void (*)(void*) __attribute__((noreturn))
The low-level `__thread_create()` function accepts a `thread_func_t` as
the entry point, which is defined more simply as:
void (*)(void *)
And then the `thread_create()` and `thread_create_named()` macros cast
the passed-in function point down to `thread_func_t`, that is, casting
away the `noreturn` attribute.
Clang considers casting between these two types to be invalid because
both the caller and the callee may have elided parts of the stack frame
save and restore, knowing that they won't be needed.
Recent Linux appears to be setting `-Wcast-function-type-strict`, which
causes this invalid cast to emit a warning, which with `-Werror` is
converted to an error, breaking the build.
This commit fixes this in the simplest possible way: adding `noreturn`
to the `thread_func_t` attribute. Since all our thread entry functions
already have this attribute, it's arguably a just a consistency fix
anyway.
I considered removing the casts in the macros, which silences the
warnings, but it turns out that Clang has a bug that won't emit this
error for implicit conversions, only explicit casts. So leaving them
there seems like a reasonable belt-and-suspenders approach. Also,
frankly, this whole mechanism seems a little undercooked inside LLVM, so
I'm content go with my intuition about the smallest, least invaisve
change.
**NOTE**: `__thread_create` is exported by `spl.ko` and has a
`thread_func_t` arg, so this is an ABI break. Whether that matters in
practice, I have no idea.
Further reading:
- https://github.com/llvm/llvm-project/commit/1aad641c793090b4d036c03e737df2ebe2c32c57
- https://github.com/llvm/llvm-project/issues/7325
- https://github.com/llvm/llvm-project/issues/41465
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #16672
Closes #16673
OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.
Official Resources
- Documentation - for using and developing this repo
- ZoL Site - Linux release info & links
- Mailing lists
- OpenZFS site - for conference videos and info on other platforms (illumos, OSX, Windows, etc)
Installation
Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.
Contribute & Develop
We have a separate document with contribution guidelines.
We have a Code of Conduct.
Release
OpenZFS is released under a CDDL license.
For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197
Supported Kernels
- The
METAfile contains the officially recognized supported Linux kernel versions. - Supported FreeBSD versions are any supported branches and releases starting from 13.0-RELEASE.