From bfe3911a91047557eb0e620f95a370aee6a248c7 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 5 Feb 2021 22:00:12 +0000 Subject: 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 Cc: Kees Cook Cc: Andy Lutomirski Cc: Will Drewry Cc: Andrew Morton Cc: Dave Airlie Cc: Daniel Vetter Cc: Lucas Stach Cc: Rasmus Villemoes Cc: Cyrill Gorcunov Cc: stable@vger.kernel.org Acked-by: Daniel Vetter # DRM depends on kcmp Acked-by: Rasmus Villemoes # systemd uses kcmp Reviewed-by: Cyrill Gorcunov Reviewed-by: Kees Cook Acked-by: Thomas Zimmermann Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@chris-wilson.co.uk --- kernel/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index aa7368c7eabf..320f1f3941b7 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -51,7 +51,7 @@ obj-y += livepatch/ obj-y += dma/ obj-y += entry/ -obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o +obj-$(CONFIG_KCMP) += kcmp.o obj-$(CONFIG_FREEZER) += freezer.o obj-$(CONFIG_PROFILING) += profile.o obj-$(CONFIG_STACKTRACE) += stacktrace.o -- cgit v1.2.3