On Thu, Oct 18, 2018 at 03:56:11PM -0700, Andrew Morton wrote: > On Thu, 18 Oct 2018 17:41:01 +0200 Christoph Hellwig <hch@xxxxxx> wrote: > > > userfaultfd contains howe-grown locking of the waitqueue lock, > > and does not disable interrupts. This relies on the fact that > > no one else takes it from interrupt context and violates an > > invariat of the normal waitqueue locking scheme. With aio poll > > it is easy to trigger other locks that disable interrupts (or > > are called from interrupt context). > > So... this is needed in 4.19.x but not earlier? Or something else? Yes.
