e0d3da982c
While discussing solutions for the teardown problem which results from
circular dependencies between timers and workqueues, where timers schedule
work from their timer callback and workqueues arm the timers from work
items, it was discovered that the recent fix to the QCA code is incorrect.
That commit fixes the obvious problem of using del_timer() instead of
del_timer_sync() and reorders the teardown calls to
destroy_workqueue(wq);
del_timer_sync(t);
This makes it less likely to explode, but it's still broken:
destroy_workqueue(wq);
/* After this point @wq cannot be touched anymore */
---> timer expires
queue_work(wq) <---- Results in a NULL pointer dereference
deep in the work queue core code.
del_timer_sync(t);
Use the new timer_shutdown_sync() function to ensure that the timers are
disarmed, no timer callbacks are running and the timers cannot be armed
again. This restores the original teardown sequence:
timer_shutdown_sync(t);
destroy_workqueue(wq);
which is now correct because the timer core silently ignores potential
rearming attempts which can happen when destroy_workqueue() drains pending
work before mopping up the workqueue.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| 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 | ||
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.