30a33669fa
io_poll_double_prepare() | io_poll_wake()
| poll->head = NULL
smp_load(&poll->head); /* NULL */ |
flags = req->flags; |
| req->flags &= ~SINGLE_POLL;
req->flags = flags | DOUBLE_POLL |
The idea behind io_poll_double_prepare() is to serialise with the
first poll entry by taking the wq lock. However, it's not safe to assume
that io_poll_wake() is not running when we can't grab the lock and so we
may race modifying req->flags.
Skip double poll setup if that happens. It's ok because the first poll
entry will only be removed when it's definitely completing, e.g.
pollfree or oneshot with a valid mask.
Fixes:
|
||
|---|---|---|
| arch | ||
| 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 | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .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 Restructured Text 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.