From: Alan Cox <alan@lxorguk.ukuu.org.uk>

Ensure current->signal->tty doesn't get freed during log_exec().

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 arch/um/kernel/exec.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletion(-)

diff -puN arch/um/kernel/exec.c~uml-tty-locking arch/um/kernel/exec.c
--- a/arch/um/kernel/exec.c~uml-tty-locking
+++ a/arch/um/kernel/exec.c
@@ -41,9 +41,11 @@ static long execve1(char *file, char __u
         long error;
 
 #ifdef CONFIG_TTY_LOG
-	task_lock(current);
+	mutex_lock(&tty_mutex);
+	task_lock(current);	/* FIXME:  is this needed ? */
 	log_exec(argv, current->signal->tty);
 	task_unlock(current);
+	mutex_unlock(&tty_mutex);
 #endif
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
_