Never mind. I just failed to see the warning on x86_32. The warning is spurious and fixed with the following commit. Applied to cgroup/for-5.5.
Thanks.
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From d7495343228f30d8206e92dccfd1c41adcfa142d Mon Sep 17 00:00:00 2001
From: Tejun Heo tj@kernel.org Date: Thu, 14 Nov 2019 14:46:51 -0800
743210386c03 ("cgroup: use cgrp->kn->id as the cgroup ID") added WARN which triggers if cgroup_id(root_cgrp) is not 1. This is fine on 64bit ino archs but on 32bit archs cgroup ID is ((gen << 32) | ino) and gen starts at 1, so the root id is 0x1_0000_0001 instead of 1 always triggering the WARN.
What we wanna make sure is that the ino part is 1. Fix it.
Reported-by: Naresh Kamboju naresh.kamboju@linaro.org Fixes: 743210386c03 ("cgroup: use cgrp->kn->id as the cgroup ID") Signed-off-by: Tejun Heo tj@kernel.org --- kernel/cgroup/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index c12dcf7dc432..53098c1d45e2 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1966,7 +1966,7 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) goto exit_root_id; } root_cgrp->kn = root->kf_root->kn; - WARN_ON_ONCE(cgroup_id(root_cgrp) != 1); + WARN_ON_ONCE(cgroup_ino(root_cgrp) != 1); root_cgrp->ancestor_ids[0] = cgroup_id(root_cgrp);
ret = css_populate_dir(&root_cgrp->self);