[Buildroot] [git commit branch/2025.08.x] package/docker-engine: depend on cgroup v2 and kernel >=5.2 without systemd

[Thomas Perale]

commit: https://git.buildroot.net/buildroot/commit/?id=d142844ce38aa8f009fabe4b6e262ab49cda7da7
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2025.08.x

Without systemd package/docker-engine requires another way to mount
/sys/fs/cgroup, so far provided by BR2_PACKAGE_CGROUPFS_MOUNT for
cgroup v1. Replace this with BR2_PACKAGE_CGROUPFS_V2_MOUNT for cgroup
v2 support. 5.2 is the minimum recommended version for cgroup v2
support according to the Docker documentation: "v4.15 or later (v5.2
or later is recommended)" [1].

Depending on the selected container runtime users may need to adjust
kernel configurations to enable options required by that runtime with
cgroup v2 (e.g. CONFIG_CGROUP_BPF for runc).

Propagate dependencies accordingly: The Docker btrfs filesystem driver
does not need a separate and lower minimum headers version,
package/mender-update-modules needs to apply the new "depends on".

[1] https://docs.docker.com/engine/containers/runmetrics/#running-docker-on-cgroup-v2

Signed-off-by: Fiona Klute (WIWA) <fiona.klute at gmx.de>
Signed-off-by: Romain Naour <romain.naour at smile.fr>
(cherry picked from commit b07b0bb4560ce49f1c4e0e54a21c28435f17bf17)
Signed-off-by: Thomas Perale <thomas.perale at mind.be>
---
 package/docker-engine/Config.in         | 13 +++++--------
 package/mender-update-modules/Config.in |  7 ++++---
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/package/docker-engine/Config.in b/package/docker-engine/Config.in
index 6338eeeef1..ae07b5e19d 100644
--- a/package/docker-engine/Config.in
+++ b/package/docker-engine/Config.in
@@ -3,11 +3,12 @@ config BR2_PACKAGE_DOCKER_ENGINE
 	depends on BR2_PACKAGE_HOST_GO_TARGET_ARCH_SUPPORTS
 	depends on BR2_PACKAGE_HOST_GO_TARGET_CGO_LINKING_SUPPORTS
 	depends on BR2_TOOLCHAIN_HAS_THREADS
+	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_2
 	depends on !BR2_TOOLCHAIN_USES_UCLIBC # containerd -> runc
 	depends on BR2_USE_MMU # containerd
+	depends on !BR2_PACKAGE_CGROUPFS_MOUNT
 	depends on BR2_PACKAGE_LIBSECCOMP_ARCH_SUPPORTS # libseccomp
-	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_17 # libseccomp
-	select BR2_PACKAGE_CGROUPFS_MOUNT if !BR2_PACKAGE_SYSTEMD # runtime dependency
+	select BR2_PACKAGE_CGROUPFS_V2_MOUNT if !BR2_PACKAGE_SYSTEMD # runtime dependency
 	select BR2_PACKAGE_CONTAINERD # runtime dependency
 	select BR2_PACKAGE_HOST_GO
 	select BR2_PACKAGE_IPTABLES # runtime dependency
@@ -22,13 +23,9 @@ if BR2_PACKAGE_DOCKER_ENGINE
 
 config BR2_PACKAGE_DOCKER_ENGINE_DRIVER_BTRFS
 	bool "btrfs filesystem driver"
-	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_12
 	help
 	  Build the btrfs filesystem driver for Docker.
 
-comment "brtfs filesystem driver needs headers >= 4.12"
-	depends on !BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_12
-
 config BR2_PACKAGE_DOCKER_ENGINE_DRIVER_DEVICEMAPPER
 	bool "devicemapper filesystem driver"
 	depends on BR2_TOOLCHAIN_HAS_THREADS # lvm2
@@ -83,11 +80,11 @@ config BR2_PACKAGE_DOCKER_ENGINE_DOCKER_INIT_NAME
 
 endif
 
-comment "docker-engine needs a glibc or musl toolchain w/ threads, headers >= 3.17"
+comment "docker-engine needs a glibc or musl toolchain w/ threads, headers >= 5.2"
 	depends on BR2_PACKAGE_HOST_GO_TARGET_ARCH_SUPPORTS
 	depends on BR2_PACKAGE_HOST_GO_TARGET_CGO_LINKING_SUPPORTS
 	depends on BR2_PACKAGE_LIBSECCOMP_ARCH_SUPPORTS
 	depends on !BR2_TOOLCHAIN_HAS_THREADS || \
 		BR2_TOOLCHAIN_USES_UCLIBC || \
-		!BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_17
+		!BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_2
 	depends on BR2_USE_MMU
diff --git a/package/mender-update-modules/Config.in b/package/mender-update-modules/Config.in
index 76158ab6c7..e71309c3d6 100644
--- a/package/mender-update-modules/Config.in
+++ b/package/mender-update-modules/Config.in
@@ -79,8 +79,9 @@ config BR2_PACKAGE_MENDER_UPDATE_MODULES_DOCKER
 	depends on BR2_TOOLCHAIN_HAS_THREADS # docker-engine, docker-cli
 	depends on !BR2_TOOLCHAIN_USES_UCLIBC # containerd -> runc
 	depends on BR2_USE_MMU # containerd
+	depends on !BR2_PACKAGE_CGROUPFS_MOUNT # docker-engine
 	depends on BR2_PACKAGE_LIBSECCOMP_ARCH_SUPPORTS # libseccomp
-	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_17 # libseccom
+	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_2 # docker-engine
 	select BR2_PACKAGE_DOCKER_ENGINE
 	select BR2_PACKAGE_DOCKER_CLI
 	select BR2_PACKAGE_JQ # runtime
@@ -97,13 +98,13 @@ config BR2_PACKAGE_MENDER_UPDATE_MODULES_DOCKER
 
 	  https://github.com/mendersoftware/mender-update-modules/tree/master/docker
 
-comment "docker support needs a glibc or musl toolchain w/ threads, headers >= 3.17"
+comment "docker support needs a glibc or musl toolchain w/ threads, headers >= 5.2"
 	depends on BR2_PACKAGE_HOST_GO_TARGET_ARCH_SUPPORTS
 	depends on BR2_PACKAGE_HOST_GO_TARGET_CGO_LINKING_SUPPORTS
 	depends on BR2_PACKAGE_LIBSECCOMP_ARCH_SUPPORTS
 	depends on !BR2_TOOLCHAIN_HAS_THREADS || \
 		BR2_TOOLCHAIN_USES_UCLIBC || \
-		!BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_17
+		!BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_2
 	depends on BR2_USE_MMU
 
 config BR2_PACKAGE_MENDER_UPDATE_MODULES_IPK