tty: Retry failed reopen if tty teardown in-progress
authorPeter Hurley <peter@hurleysoftware.com>
Sun, 10 Jan 2016 05:13:45 +0000 (21:13 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 27 Jan 2016 07:17:54 +0000 (23:17 -0800)
commit7f22f6c935cda600660e623a411fe380015d28d9
tree1083661f1cad2ddd47a7770b2d6f4470da37d157
parent0bfd464d3fdd5bb322f9cace4cc47f1796545cf7
tty: Retry failed reopen if tty teardown in-progress

A small window exists where a tty reopen will observe the tty
just prior to imminent teardown (tty->count == 0); in this case, open()
returns EIO to userspace.

Instead, retry the open after checking for signals and yielding;
this interruptible retry loop allows teardown to commence and initialize
a new tty on retry. Never retry the BSD master pty reopen; there is no
guarantee the pty pair teardown is imminent since the slave file
descriptors may remain open indefinitely.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org> # 4.4
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/tty_io.c