[SRU][Trusty][V2][PATCH 0/1] tty: fix stall caused by missing memory barrier in drivers/tty/n_tty.c

[Joseph Salisbury]

BugLink: http://bugs.launchpad.net/bugs/1512815

== Trusty SRU Justification ==

The bug reported ran into a program stall on a x86_64 server, where n_tty_read() 
was waiting for data even if there was data in the buffer in the pty.

Commit e81107d fixes this issue and has been in mainline since v4.3-rc5.  The commit has
been cc'd to stable, but has not yet landed in upstream 3.13.y.

The commit is a clean cherry-pick for Vivid and Wily.  However, Trusty requires a 
backport, so that is the reason this SRU request is separate.

This is V2 of the backport.  The first backport mistakenly had and extra call to spin_unlock_irqrestore().

== Fix ==

commit e81107d4c6bd098878af9796b24edc8d4a9524fd
Author: Kosuke Tatsukawa <tatsu at ab.jp.nec.com>
Date:   Fri Oct 2 08:27:05 2015 +0000

    tty: fix stall caused by missing memory barrier in drivers/tty/n_tty.c


== Test Case ==

A test kernel was built with this patch and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug.


Kosuke Tatsukawa (1):
  tty: fix stall caused by missing memory barrier in drivers/tty/n_tty.c

 drivers/tty/n_tty.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

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1.9.1