Re: slab-out-of-bounds in iov_iter_revert()

[Al Viro]

On Fri, Sep 11, 2020 at 05:59:04PM -0400, Qian Cai wrote:
> Super easy to reproduce on today's mainline by just fuzzing for a few minutes
> on virtiofs (if it ever matters). Any thoughts?

Usually happens when ->direct_IO() fucks up and reports the wrong amount
of data written/read.  We had several bugs like that in the past - see
e.g. 85128b2be673 (fix nfs O_DIRECT advancing iov_iter too much).

Had there been any recent O_DIRECT-related patches on the filesystems
involved?