mirror of
https://github.com/torvalds/linux.git
synced 2026-08-23 00:15:27 +02:00
Linux kernel source tree
3c27a36f27
Currently reference counts are implemented by locking service_spinlock and then incrementing the service's ->ref_count field, calling kfree() when the last reference has been dropped. But at the same time, there's code in multiple places that dereferences pointers to services without having a reference, so there could be a race there. It should be possible to avoid taking any lock in unlock_service() or service_release() because we are setting a single array element to NULL, and on service creation, a mutex is locked before looking for a NULL spot to put the new service in. Using a struct kref and RCU-delaying the freeing of services fixes this race condition while still making it possible to skip grabbing a reference in many places. Also it avoids the need to acquire a single spinlock when e.g. taking a reference on state->services[i] when somebody else is in the middle of taking a reference on state->services[j]. Signed-off-by: Marcelo Diop-Gonzalez <marcgonzalez@google.com> Link: https://lore.kernel.org/r/3bf6f1ec6ace64d7072025505e165b8dd18b25ca.1581532523.git.marcgonzalez@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.