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The linux-next integration testing tree
4d28df6152
During checkpointing and restore of userspace tasks we bumped into the situation, that it's not possible to restore the tasks, which user namespace does not have uid 0 or gid 0 mapped. People create user namespace mappings like they want, and there is no a limitation on obligatory uid and gid "must be mapped". So, if there is no uid 0 or gid 0 in the mapping, it's impossible to restore mm->exe_file of the processes belonging to this user namespace. Also, there is no a workaround. It's impossible to create a temporary uid/gid mapping, because only one write to /proc/[pid]/uid_map and gid_map is allowed during a namespace lifetime. If there is an entry, then no more mapings can't be written. If there isn't an entry, we can't write there too, otherwise user task won't be able to do that in the future. The patch changes the check, and looks for CAP_SYS_ADMIN instead of zero uid and gid. This allows to restore a task independently of its user namespace mappings. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> CC: Andrew Morton <akpm@linux-foundation.org> CC: Serge Hallyn <serge@hallyn.com> CC: "Eric W. Biederman" <ebiederm@xmission.com> CC: Oleg Nesterov <oleg@redhat.com> CC: Michal Hocko <mhocko@suse.com> CC: Andrei Vagin <avagin@openvz.org> CC: Cyrill Gorcunov <gorcunov@openvz.org> CC: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com> CC: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> |
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| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.