Fix the pid and ppid variables in multithreaded processes.

pid is currently equal to the Linux-side PID: i.e., from userspace's
perspective, the thread ID.  tgid is equal to the thread ID of the parent.  Both
of these are at best inconvenient and at worst wrong: they should both use the
thread group ID of their respective task, which corresponds to the
userspace-visible PID.

Orabug: 18412802
Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>

diff --git a/dtrace/dtrace_dif.c b/dtrace/dtrace_dif.c
index 0d0020bb9f3ec42f2dfdd7b34a5c5f8f44025035..52816e942043103678693918958cf8be3ac85019 100644 (file)
--- a/dtrace/dtrace_dif.c
+++ b/dtrace/dtrace_dif.c
@@ -2243,7 +2243,7 @@ static uint64_t dtrace_dif_variable(dtrace_mstate_t *mstate,
                 * It is always safe to dereference current, it always points
                 * to a valid task_struct.
                 */
-               return (uint64_t)current->pid;
+               return (uint64_t)current->tgid;
 
        case DIF_VAR_PPID:
                if (!dtrace_priv_proc(state))
@@ -2256,7 +2256,7 @@ static uint64_t dtrace_dif_variable(dtrace_mstate_t *mstate,
                 * Additionally, it is safe to dereference one's parent, since
                 * it is never NULL after process birth.
                 */
-               return (uint64_t)current->real_parent->pid;
+               return (uint64_t)current->real_parent->tgid;
 
        case DIF_VAR_TID:
                return (uint64_t)current->pid;