on pre-3.12 kernel, there is no support for getting subsys name. because the cgroup_subsys_state struct has no member ss. the current use MEMBER_OFFSET to dectect the exists for ss member which is the wrong method. This patch fix it by using MEMBER_EXISTS. on centos7, without this patch: crash> showcg 1 showcg: invalid kernel virtual address: ff9987beef203060 type: "cgroup_subsys->name" with this patch applys: crash> showcg 1 cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / cgroup: / Signed-off-by: Wang Long <w(a)laoqinren.net&gt; --- extensions/proccgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/extensions/proccgroup.c b/extensions/proccgroup.c index c2c251d..c53b8ce 100644 --- a/extensions/proccgroup.c +++ b/extensions/proccgroup.c @@ -33,7 +33,7 @@ proccgroup_init(void) error(FATAL, "Unrecognised or disabled cgroup support\n"); } - if (!MEMBER_OFFSET("cgroup_subsys_state", "ss")) { + if (!MEMBER_EXISTS("cgroup_subsys_state", "ss")) { have_ss_member = false; error(WARNING, "pre-3.12 kernel detected, no support for getting subsys name\n"); } else -- 1.8.3.1