e1ad8eaa80
[ Upstream commit d90cfe20562407d9f080d24123078d666d730707 ]
The purpose of the rehash delayed work is to reduce the number of masks
(eRPs) used by an ACL region as the eRP bank is a global and limited
resource.
This is done in three steps:
1. Creating a new set of masks and a new ACL region which will use the
new masks and to which the existing filters will be migrated to. The
new region is assigned to 'vregion->region' and the region from which
the filters are migrated from is assigned to 'vregion->region2'.
2. Migrating all the filters from the old region to the new region.
3. Destroying the old region and setting 'vregion->region2' to NULL.
Only the second steps is performed under the 'vregion->lock' mutex
although its comments says that among other things it "Protects
consistency of region, region2 pointers".
This is problematic as the first step can race with filter insertion
from user space that uses 'vregion->region', but under the mutex.
Fix by holding the mutex across the entirety of the delayed work and not
only during the second step.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| 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.