pty race

The n_tty_write function in drivers/tty/n_tty.c in the Linux kernel through 3.14.3 does not properly manage tty driver access in the “LECHO & !OPOST” case, which allows local users to cause a denial of service (memory corruption and system crash) or gain privileges by triggering a race condition involving read and write operations with long strings.
Taking a look at the git history of the Linux kernel it turns out that all kernels between c56a00a165712fd73081f40044b1e64407bb1875 (march 2012) and 64325a3be08d364a62ee8f84b2cf86934bc2544a (january 2013) are not affected by this vuln as tty_insert_flip_string_fixed_flag() was internally locked there.
Fixed from 4291086b1f081b869c6d79e5b7441633dc3ace00 and present from d945cb9cce20ac7143c2de8d88b187f62db99bdc