Fix UTS corruption during clone(CLONE_NEWUTS)

struct utsname is copied from master one without any exclusion.

Here is sample output from one proggie doing

	sethostname("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
	sethostname("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb");

and another

clone(,, CLONE_NEWUTS, ...)
uname()

hostname = 'aaaaaaaaaaaaaaaaaaaaaaaaabbbbb' hostname = 'bbbaaaaaaaaaaaaaaaaaaaaaaaaaaa' hostname = 'aaaaaaaabbbbbbbbbbbbbbbbbbbbbb' hostname = 'aaaaaaaaaaaaaaaaaaaaaaaaaabbbb' hostname = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaabb' hostname = 'aaabbbbbbbbbbbbbbbbbbbbbbbbbbb' hostname = 'bbbbbbbbbbbbbbbbaaaaaaaaaaaaaa'

Hostname is sometimes corrupted.

Yes, even _the_ simplest namespace activity had bug in it. :-(

Signed-off-by Alexey Dobriyan <[email protected]>

---

 kernel/utsname.c |    2 ++
 1 file changed, 2 insertions(+)

kernel/utsname.c +2 -1

@@ -28,7 +28,9 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
 	if (!ns)
 		return ERR_PTR(-ENOMEM);
 
+	down_read(&uts_sem);
 	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+	up_read(&uts_sem);
 	kref_init(&ns->kref);
 	return ns;
 }
 
-

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