- Cache a reference to the credential of the thread that starts a ktrace in

  struct proc as p_tracecred alongside the current cache of the vnode in
  p_tracep.  This credential is then used for all later ktrace operations on
  this file rather than using the credential of the current thread at the
  time of each ktrace event.
- Now that we have multiple ktrace-related items in struct proc that are
  pointers, rename p_tracep to p_tracevp to make it less ambiguous.

Requested by:	rwatson (1)

1 files changed, 7 insertions, 3 deletions

diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 65a3360..0c24cc6 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -626,11 +626,15 @@ again:
 	 * Copy traceflag and tracefile if enabled.
 	 */
 	mtx_lock(&ktrace_mtx);
-	KASSERT(p2->p_tracep == NULL, ("new process has a ktrace vnode"));
+	KASSERT(p2->p_tracevp == NULL, ("new process has a ktrace vnode"));
 	if (p1->p_traceflag & KTRFAC_INHERIT) {
 		p2->p_traceflag = p1->p_traceflag;
-		if ((p2->p_tracep = p1->p_tracep) != NULL)
-			VREF(p2->p_tracep);
+		if ((p2->p_tracevp = p1->p_tracevp) != NULL) {
+			VREF(p2->p_tracevp);
+			KASSERT(p1->p_tracecred != NULL,
+			    ("ktrace vnode with no cred"));
+			p2->p_tracecred = crhold(p1->p_tracecred);
+		}
 	}
 	mtx_unlock(&ktrace_mtx);
 #endif