On 15/06/2023 02:18, Gustavo A. R. Silva wrote:
> Address the following -Wstringop-overflow warnings seen when
> built with ARM architecture and aspeed_g4_defconfig configuration
> (notice that under this configuration CGROUP_SUBSYS_COUNT == 0):
> kernel/cgroup/cgroup.c:1208:16: warning: 'find_existing_css_set' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
> kernel/cgroup/cgroup.c:1258:15: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
> kernel/cgroup/cgroup.c:6089:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
> kernel/cgroup/cgroup.c:6153:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
>
> These changes are based on commit d20d30ebb199 ("cgroup: Avoid compiler
> warnings with no subsystems").
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> ---
> kernel/cgroup/cgroup.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index cd497b90e11a..1ee76e62eb98 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -1200,6 +1200,9 @@ static struct css_set *find_css_set(struct css_set *old_cset,
> unsigned long key;
> int ssid;
>
> + if (!CGROUP_HAS_SUBSYS_CONFIG)
> + return NULL;
> +
> lockdep_assert_held(&cgroup_mutex);
>
> /* First see if we already have a cgroup group that matches
> @@ -6045,6 +6048,9 @@ int __init cgroup_init(void)
> struct cgroup_subsys *ss;
> int ssid;
>
> + if (!CGROUP_HAS_SUBSYS_CONFIG)
> + return -EINVAL;
> +
> BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16);
> BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files));
> BUG_ON(cgroup_init_cftypes(NULL, cgroup_psi_files));
This change (which landed in linux-next) causes a boot failure on my
(arm32) board because the cgroup filesystem isn't created which upsets
systemd:
[ 11.474767] systemd[1]: Failed to mount tmpfs at /sys/fs/cgroup: No such file or directory
[ 11.489933] systemd[1]: Failed to mount cgroup at /sys/fs/cgroup/systemd: No such file or directory
[!!!!!!] Failed to mount API filesystems.
Reverting this commit on the head of linux-next gets the board working
again.
Thanks,
Steve
