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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2021-02-05 22:00:12 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-04 11:38:41 +0100 |
| commit | 1ea36020950d44ef9152d832887a0c1cee0edee2 (patch) | |
| tree | 6521cceac8b25a64a8f9186b4bfca1acaf65e8a0 /init | |
| parent | 834c7ec6af441a3630fc60d72522e06dc65003eb (diff) | |
| download | linux-1ea36020950d44ef9152d832887a0c1cee0edee2.tar.gz linux-1ea36020950d44ef9152d832887a0c1cee0edee2.tar.bz2 linux-1ea36020950d44ef9152d832887a0c1cee0edee2.zip | |
kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE
commit bfe3911a91047557eb0e620f95a370aee6a248c7 upstream.
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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index 0872a5a2e759..d559abf38c90 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1194,6 +1194,7 @@ endif # NAMESPACES config CHECKPOINT_RESTORE bool "Checkpoint/restore support" select PROC_CHILDREN + select KCMP default n help Enables additional kernel features in a sake of checkpoint/restore. @@ -1737,6 +1738,16 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS config ARCH_HAS_MEMBARRIER_SYNC_CORE bool +config KCMP + bool "Enable kcmp() system call" if EXPERT + help + Enable the kernel resource comparison system call. It provides + user-space with the ability to compare two processes to see if they + share a common resource, such as a file descriptor or even virtual + memory space. + + If unsure, say N. + config RSEQ bool "Enable rseq() system call" if EXPERT default y |