Re: iov_iter_pipe warning.

[Al Viro]

On Tue, Apr 11, 2017 at 04:53:36PM -0400, Dave Jones wrote:
>  > 		if (WARN_ON(pipe->nrbufs)) {
>  > 			printk(KERN_ERR "->splice_write = %p",
>  > 				sd->u.file->f_op->splice_write);
>  > 		}
>  > 	}
> 
> Ah, missed adding this 2nd WARN_ON.

Good - it means that we don't have to chase memory corruption yet.  That
smells like some ->splice_write() claiming it has copied more than it
has drained from the pipe.

> I'll turn it back off, and retry with the missing WARN from above added.

Please, do.  And it would be nice if you printed sd->u.file->f_op as well
(in the same printk).