Re: [Qemu-devel] [PULL v4 00/35] Misc patches for 2018-12-21

[Peter Maydell]

On Fri, 4 Jan 2019 at 07:59, Paolo Bonzini <address@hidden> wrote:
>
> On 03/01/19 19:37, Peter Maydell wrote:
> > On Sat, 22 Dec 2018 at 08:41, Paolo Bonzini <address@hidden> wrote:
> > Interestingly, I have today run into "make: write error: stdout"
> > with the existing make check infrastructure. [...]
> > I presume that something in one of the tests we're running,
> > likely QEMU itself, ends up setting stdout to non-blocking.
> > This while rune *used* to be entirely reliable, so maybe
> > something recent has changed ?
>
> I don't know... I tried running make check under "strace -e fcntl" and I
> didn't find any occurrences of fcntl(1, O_SETFL, ...|O_NONBLOCK).
> Perhaps you can add a check after every invocation of a test executable.

> Are you going to apply the pull request since the bug is preexisting?

The pull request takes the problem from "occasionally shows up
in by-hand running of make check in a while loop" to "reliably
causes my automated tests to fail every time". I can't apply
a pullreq that does that, so we need to find at least a workaround.
I'm not sure why your test harness makes it much more likely
that the problem manifests.

(The shell will typically clear the O_NONBLOCK flag on its terminal
before waiting for interactive input, which is why this is a
problem when running make check inside a while loop or in my
pull test script which runs make check for several trees in
succession, but not an issue for individual runs on the command line.)

thanks
-- PMM