4f07ec0d76
The recent rework of the requeue PI code introduced a possibility for
going back to user space in inconsistent state:
CPU 0 CPU 1
requeue_futex()
if (lock_pifutex_user()) {
dequeue_waiter();
wake_waiter(task);
sched_in(task);
return_from_futex_syscall();
---> Inconsistent state because PI state is not established
It becomes worse if the woken up task immediately exits:
sys_exit();
attach_pistate(vpid); <--- FAIL
Attach the pi state before dequeuing and waking the waiter. If the waiter
gets a spurious wakeup before the dequeue operation it will wait in
futex_requeue_pi_wakeup_sync() and therefore cannot return and exit.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.