[PATCH] initramfs: Fix a missing-check bug in init/initramfs.c

[Gen Zhang]

In dir_add(), de and de->name are allocated by kmalloc() and kstrdup().
And de->name is dereferenced in the following codes. However, memory
allocation functions such as kmalloc() and kstrdup() may fail.
Dereferencing this de->name null pointer may cause the kernel go wrong.
Thus we should check this allocation.
Further, if kstrdup() returns NULL, we should free de and panic().

Signed-off-by: Gen Zhang <blackgod016...@gmail.com>

---
diff --git a/init/initramfs.c b/init/initramfs.c
index 178130f..dc8063f 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -125,6 +125,10 @@ static void __init dir_add(const char *name, time64_t 
mtime)
                panic("can't allocate dir_entry buffer");
        INIT_LIST_HEAD(&de->list);
        de->name = kstrdup(name, GFP_KERNEL);
+       if (!de->name) {
+               kfree(de);
+               panic("can't allocate dir_entry name buffer");
+       }
        de->mtime = mtime;
        list_add(&de->list, &dir_list);
 }