Messages in this thread | | | Date | Fri, 27 Sep 2013 13:32:30 -0400 | From | Peter Hurley <> | Subject | Re: [PATCH] tty: Fix pty master read() after slave closes |
| |
On 09/27/2013 01:27 PM, Peter Hurley wrote: > Commit f95499c3030fe1bfad57745f2db1959c5b43dca8, > n_tty: Don't wait for buffer work in read() loop > creates a race window which can cause a pty master read() > to miss the last pty slave write(s) and return -EIO instead, > thus signalling the pty slave is closed. This can happen when > the pty slave is written and immediately closed but before the > tty buffer i/o loop receives the new input; the pty master > read() is scheduled, sees its read buffer is empty and the > pty slave has been closed, and exits. > > Because tty_flush_to_ldisc() has significant performance impact > for parallel i/o, rather than revert the commit, special case this > condition (ie., when the read buffer is empty and the 'other' pty > has been closed) and, only then, wait for buffer work to complete > before re-testing if the read buffer is still empty. > > As before, subsequent pty master reads return any available data > until no more data is available, and then returns -EIO to > indicate the pty slave has closed. > > Reported-by: Mikael Pettersson <mikpelinux@gmail.com> > Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
I tested this patch with the gcc ada ACATS testsuite and got this summary so all seems ok with this patch.
=== acats Summary === # of expected passes 805 # of unexpected failures 0
...
=== acats Summary === # of expected passes 772 # of unexpected failures 0
...
=== acats Summary === # of expected passes 743 # of unexpected failures 0
Mikael,
I'd appreciate if you could re-test with this patch and confirm the issue is fixed.
Regards, Peter Hurley
| |