1 files changed, 4 insertions, 1 deletions

diff --git a/procps/kill.c b/procps/kill.c
index cd189bcd6..8e4213730 100644
--- a/procps/kill.c
+++ b/procps/kill.c
@@ -158,7 +158,8 @@ int kill_main(int argc, char **argv)
         if (killall5) {
                 pid_t sid;
                 procps_status_t* p = NULL;
-                int ret = 0;
+                /* compat: exitcode 2 is "no one was signaled" */
+                int ret = 2;
 
                 /* Find out our session id */
                 sid = getsid(pid);
@@ -170,6 +171,7 @@ int kill_main(int argc, char **argv)
                         int i;
 
                         if (p->sid == (unsigned)sid
+                         || p->sid == 0 /* compat: kernel thread, don't signal it */
                          || p->pid == (unsigned)pid
                          || p->pid == 1
                         ) {
@@ -200,6 +202,7 @@ int kill_main(int argc, char **argv)
                                         goto dont_kill;
                         }
                         kill(p->pid, signo);
+                        ret = 0;
  dont_kill: ;
                 }
  resume: