[PATCH] wrong pid in siginfo_t

If a signal is sent via kill() or tkill() the kernel fills in the wrong
PID value in the siginfo_t structure (obviously only if the handler has
SA_SIGINFO set).

POSIX specifies the the si_pid field is filled with the process ID, and
in Linux parlance that's the "thread group" ID, not the thread ID.

kernel/signal.c

@@ -2082,7 +2082,7 @@ sys_kill(int pid, int sig)
 	info.si_signo = sig;
 	info.si_errno = 0;
 	info.si_code = SI_USER;
-	info.si_pid = current->pid;
+	info.si_pid = current->tgid;
 	info.si_uid = current->uid;
 
 	return kill_something_info(sig, &info, pid);
@@ -2105,7 +2105,7 @@ sys_tkill(int pid, int sig)
 	info.si_signo = sig;
 	info.si_errno = 0;
 	info.si_code = SI_TKILL;
-	info.si_pid = current->pid;
+	info.si_pid = current->tgid;
 	info.si_uid = current->uid;
 
 	read_lock(&tasklist_lock);