14afc59361
The bfq_find_set_group() function takes as input a blkcg (which represents a cgroup) and retrieves the corresponding bfq_group, then it updates the bfq internal group hierarchy (see comments inside the function for why this is needed) and finally it returns the bfq_group. In the hierarchy update cycle, the pointer holding the correct bfq_group that has to be returned is mistakenly used to traverse the hierarchy bottom to top, meaning that in each iteration it gets overwritten with the parent of the current group. Since the update cycle stops at root's children (depth = 2), the overwrite becomes a problem only if the blkcg describes a cgroup at a hierarchy level deeper than that (depth > 2). In this case the root's child that happens to be also an ancestor of the correct bfq_group is returned. The main consequence is that processes contained in a cgroup at depth greater than 2 are wrongly placed in the group described above by BFQ. This commits fixes this problem by using a different bfq_group pointer in the update cycle in order to avoid the overwrite of the variable holding the original group reference. Reported-by: Kwon Je Oh <kwonje.oh2@gmail.com> Signed-off-by: Carlo Nonato <carlo.nonato95@gmail.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| 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.