X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=kernel%2Fsys.c;h=0b6ec0e7936f02ebb92477dd12951169a2bc7218;hb=19ca5d27e15c10d8529984ecd98dcba2637edcd2;hp=7ef7f6054c2851ac44d96e49eea4e55214fc0159;hpb=7d7185c818925ba5fe90efa75840d0b415032774;p=linux-2.6-omap-h63xx.git

diff --git a/kernel/sys.c b/kernel/sys.c
index 7ef7f6054c2..0b6ec0e7936 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1372,18 +1372,29 @@ asmlinkage long sys_getsid(pid_t pid)
 asmlinkage long sys_setsid(void)
 {
 	struct task_struct *group_leader = current->group_leader;
-	struct pid *pid;
+	pid_t session;
 	int err = -EPERM;
 
 	mutex_lock(&tty_mutex);
 	write_lock_irq(&tasklist_lock);
 
-	pid = find_pid(PIDTYPE_PGID, group_leader->pid);
-	if (pid)
+	/* Fail if I am already a session leader */
+	if (group_leader->signal->leader)
+		goto out;
+
+	session = group_leader->pid;
+	/* Fail if a process group id already exists that equals the
+	 * proposed session id.
+	 *
+	 * Don't check if session id == 1 because kernel threads use this
+	 * session id and so the check will always fail and make it so
+	 * init cannot successfully call setsid.
+	 */
+	if (session > 1 && find_task_by_pid_type(PIDTYPE_PGID, session))
 		goto out;
 
 	group_leader->signal->leader = 1;
-	__set_special_pids(group_leader->pid, group_leader->pid);
+	__set_special_pids(session, session);
 	group_leader->signal->tty = NULL;
 	group_leader->signal->tty_old_pgrp = 0;
 	err = process_group(group_leader);