X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fsys.c;h=0b6ec0e7936f02ebb92477dd12951169a2bc7218;hb=a145410dccdb44f81d3b56763ef9b6f721f4e47c;hp=c93d37f71aef98b23a9f43f6ac7d1f37b9ff20fd;hpb=c0e4077c946104e5d8a62f835dcdca5c79c8af7d;p=linux-2.6

diff --git a/kernel/sys.c b/kernel/sys.c
index c93d37f71a..0b6ec0e793 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1202,69 +1202,24 @@ asmlinkage long sys_times(struct tms __user * tbuf)
 	 */
 	if (tbuf) {
 		struct tms tmp;
+		struct task_struct *tsk = current;
+		struct task_struct *t;
 		cputime_t utime, stime, cutime, cstime;
 
-#ifdef CONFIG_SMP
-		if (thread_group_empty(current)) {
-			/*
-			 * Single thread case without the use of any locks.
-			 *
-			 * We may race with release_task if two threads are
-			 * executing. However, release task first adds up the
-			 * counters (__exit_signal) before  removing the task
-			 * from the process tasklist (__unhash_process).
-			 * __exit_signal also acquires and releases the
-			 * siglock which results in the proper memory ordering
-			 * so that the list modifications are always visible
-			 * after the counters have been updated.
-			 *
-			 * If the counters have been updated by the second thread
-			 * but the thread has not yet been removed from the list
-			 * then the other branch will be executing which will
-			 * block on tasklist_lock until the exit handling of the
-			 * other task is finished.
-			 *
-			 * This also implies that the sighand->siglock cannot
-			 * be held by another processor. So we can also
-			 * skip acquiring that lock.
-			 */
-			utime = cputime_add(current->signal->utime, current->utime);
-			stime = cputime_add(current->signal->utime, current->stime);
-			cutime = current->signal->cutime;
-			cstime = current->signal->cstime;
-		} else
-#endif
-		{
+		spin_lock_irq(&tsk->sighand->siglock);
+		utime = tsk->signal->utime;
+		stime = tsk->signal->stime;
+		t = tsk;
+		do {
+			utime = cputime_add(utime, t->utime);
+			stime = cputime_add(stime, t->stime);
+			t = next_thread(t);
+		} while (t != tsk);
 
-			/* Process with multiple threads */
-			struct task_struct *tsk = current;
-			struct task_struct *t;
-
-			read_lock(&tasklist_lock);
-			utime = tsk->signal->utime;
-			stime = tsk->signal->stime;
-			t = tsk;
-			do {
-				utime = cputime_add(utime, t->utime);
-				stime = cputime_add(stime, t->stime);
-				t = next_thread(t);
-			} while (t != tsk);
+		cutime = tsk->signal->cutime;
+		cstime = tsk->signal->cstime;
+		spin_unlock_irq(&tsk->sighand->siglock);
 
-			/*
-			 * While we have tasklist_lock read-locked, no dying thread
-			 * can be updating current->signal->[us]time.  Instead,
-			 * we got their counts included in the live thread loop.
-			 * However, another thread can come in right now and
-			 * do a wait call that updates current->signal->c[us]time.
-			 * To make sure we always see that pair updated atomically,
-			 * we take the siglock around fetching them.
-			 */
-			spin_lock_irq(&tsk->sighand->siglock);
-			cutime = tsk->signal->cutime;
-			cstime = tsk->signal->cstime;
-			spin_unlock_irq(&tsk->sighand->siglock);
-			read_unlock(&tasklist_lock);
-		}
 		tmp.tms_utime = cputime_to_clock_t(utime);
 		tmp.tms_stime = cputime_to_clock_t(stime);
 		tmp.tms_cutime = cputime_to_clock_t(cutime);
@@ -1417,18 +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);