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A mirror of the official Linux kernel repository just in case
a8ebd17160
Replace send_sig and force_sig in __do_SAK with group_send_sig_info the general helper for sending a signal to a process group. This is wordier but it allows specifying PIDTYPE_SID so that the signal code knows the signal went to a session. Both force_sig() and send_sig(..., 1) specify SEND_SIG_PRIV and the new call of group_send_sig_info does that explicitly. This is enough to ensure even a pid namespace init is killed. The global init remains unkillable. The guarantee that __do_SAK tries to provide is a clean path to login to a machine. As the global init is unkillable, if it chooses to hold open a tty it can violate this guarantee. A technique other than killing processes would be needed to provide this guarantee to userspace. The only difference between force_sig and send_sig when sending SIGKILL is that SIGNAL_UNKILLABLE is cleared. This has no affect on the processing of a signal sent with SEND_SIG_PRIV by any process, making it unnecessary, and not behavior that needs to be preserved. force_sig was used originally because it did not take as many locks as send_sig. Today send_sig, force_sig and group_send_sig_info take the same locks when delivering a signal. group_send_sig_info also contains a permission check that force_sig and send_sig do not. However the presence of SEND_SIG_PRIV makes the permission check a noop. So the permission check does not result in any behavioral differences. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
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| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
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| 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.
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.