Messages in this thread | | | Date | Sat, 28 Sep 2013 19:36:44 +0200 | From | Mikael Pettersson <> | Subject | Re: [PATCH] tty: Fix pty master read() after slave closes |
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Peter Hurley writes: > 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.
I did a big pile of gcc bootstrap + regression test runs today with this patch, and everything looks good. Thus:
Tested-by: Mikael Pettersson <mikpelinux@gmail.com>
Thanks,
/Mikael
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