On Thu, Oct 24, 2024 at 6:19 AM Steven Rostedt [off-list ref] wrote:

On Thu, 24 Oct 2024 03:40:12 -0700
Jordan Rome [off-list ref] wrote:

quoted

+TRACE_EVENT(capable,
+
+     TP_PROTO(const struct cred *cred, struct user_namespace *targ_ns,
+             struct user_namespace *capable_ns, int cap, unsigned int opts, int ret),
+
+     TP_ARGS(cred, targ_ns, capable_ns, cap, opts, ret),
+
+     TP_STRUCT__entry(
+             __field(const struct cred *, cred)
+             __field(struct user_namespace *, targ_ns)
+             __field(struct user_namespace *, capable_ns)
+             __field(int, cap)
+             __field(unsigned int, opts)
+             __field(int, ret)
+     ),
+
+     TP_fast_assign(
+             __entry->cred       = cred;
+             __entry->targ_ns    = targ_ns;
+             __entry->capable_ns = capable_ns;
+             __entry->cap        = cap;
+             __entry->opts       = opts;
+             __entry->ret        = ret;
+     ),
+
+     TP_printk("cap %d, opts %u, ret %d",
+             __entry->cap, __entry->opts, __entry->ret)
+);
+

You record cred, targ_ns and capable_ns but don't use it in TP_printk?

It's fine to print pointers there. Is there a reason you do not?

Are those pointers really useful for anything? Maybe it's better to
print ns->ns.inum instead? At least that's something that is usable
from user space side, no?

-- Steve