Re: [PATCH AUTOSEL 5.5 542/542] pipe: use exclusive waits when reading or writing

On Tue, Feb 18, 2020 at 1:51 AM Andrei Vagin avagin@gmail.com wrote:

This patch breaks one of CRIU tests. Here is a small reproducer:

Good catch.

The quick fix looks like this:

That one works, but is not really right.

The things that change the number of readers or writers should simply use "wake_up_all()".

I thought we did that already, but no - there _was_ one place where we did it, but that was for the pipe buffer size case, and in that case it's actually pointless. That case acts just like a "new space or data was added"

So I think the right fix is the attached patch. Since you had such a lovely test-case, let me go test it too ;)

Linus