UBUNTU: SAUCE: seq_file: Disallow extremely large seq buffer allocations

UBUNTU: SAUCE: seq_file: Disallow extremely large seq buffer allocations

There is no reasonable need for a buffer larger than this,
and it avoids int overflow pitfalls.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
CVE-2021-33909
Fixes: 058504edd026 ("fs/seq_file: fallback to vmalloc allocation")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Juerg Haefliger <juergh@canonical.com>
Acked-by: Benjamin M Romer <benjamin.romer@canonical.com>