tty: fix data race between tty_init_dev and flush of buf
There can be a race, if receive_buf call comes before
tty initialization completes in n_tty_open and tty->disc_data
may be NULL.
CPU0 CPU1
---- ----
000|n_tty_receive_buf_common() n_tty_open()
-001|n_tty_receive_buf2() tty_ldisc_open.isra.3()
-002|tty_ldisc_receive_buf(inline) tty_ldisc_setup()
Using ldisc semaphore lock in tty_init_dev till disc_data
initializes completely.
Change-Id: I5a5ac8ee5c2c7a260e447b6dae6fd2ea423212d1
Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: b027e2298bd588d6fa36ed2eda97447fb3eac078
Git-repo: https://kernel.googlesource.com/pub/scm/linux/kernel/git/gregkh/tty/
Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org>
3 files changed