[S390] init task memory faults.

Lock for mmap_sem is missing on page fault retry for init task
when it fails due to out of memory.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 44f0cda..a393c30 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -355,6 +355,7 @@ out_of_memory:
        up_read(&mm->mmap_sem);
        if (tsk->pid == 1) {
                yield();
+               down_read(&mm->mmap_sem);
                goto survive;
        }
        printk("VM: killing process %s\n", tsk->comm);