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Chris Wilson bfe3911a91 kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE
Userspace has discovered the functionality offered by SYS_kcmp and has
started to depend upon it. In particular, Mesa uses SYS_kcmp for
os_same_file_description() in order to identify when two fd (e.g. device
or dmabuf) point to the same struct file. Since they depend on it for
core functionality, lift SYS_kcmp out of the non-default
CONFIG_CHECKPOINT_RESTORE into the selectable syscall category.

Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to
deduplicate the per-service file descriptor store.

Note that some distributions such as Ubuntu are already enabling
CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> # DRM depends on kcmp
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> # systemd uses kcmp
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@chris-wilson.co.uk
2021-02-16 09:59:41 +01:00
arch Kbuild fixes for v5.11 (3rd) 2021-02-14 11:36:32 -08:00
block block-5.11-2021-02-05 2021-02-06 14:40:27 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto X.509: Fix crash caused by NULL pointer 2021-01-20 11:33:51 -08:00
Documentation Merge branch 'for-5.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2021-02-13 12:25:42 -08:00
drivers kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE 2021-02-16 09:59:41 +01:00
fs kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE 2021-02-16 09:59:41 +01:00
include kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE 2021-02-16 09:59:41 +01:00
init kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE 2021-02-16 09:59:41 +01:00
ipc Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
kernel kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE 2021-02-16 09:59:41 +01:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-02-10 11:33:39 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm, slub: better heuristic for number of cpus when calculating slab order 2021-02-10 11:19:27 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-02-10 11:33:39 -08:00
samples ARM: SoC drivers for v5.11 2020-12-16 16:38:41 -08:00
scripts Kbuild fixes for v5.11 (3rd) 2021-02-14 11:36:32 -08:00
security cap: fix conversions on getxattr 2021-01-28 10:22:48 +01:00
sound ALSA: hda/via: Apply the workaround generically for Clevo machines 2021-01-26 18:05:03 +01:00
tools kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE 2021-02-16 09:59:41 +01:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM/arm64 fixes for 5.11, take #2 2021-01-25 18:52:01 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-01-29 15:00:23 +01:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap MAINTAINERS: update Andrey Ryabinin's email address 2021-02-09 17:26:44 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: dccp: move Gerrit Renker to CREDITS 2021-01-14 10:53:49 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'for-5.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2021-02-13 12:25:42 -08:00
Makefile Linux 5.11 2021-02-14 14:32:24 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.