Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at fs/iomap.c:993

On Mon, Sep 18, 2017 at 09:28:55AM -0600, Jens Axboe wrote:

On 09/18/2017 09:27 AM, Christoph Hellwig wrote:

quoted

On Mon, Sep 18, 2017 at 08:26:05PM +0530, Abdul Haleem wrote:

quoted

Hi,

A warning is triggered from:

file fs/iomap.c in function iomap_dio_rw

    if (ret)
        goto out_free_dio;

    ret = invalidate_inode_pages2_range(mapping,
            start >> PAGE_SHIFT, end >> PAGE_SHIFT);

quoted

quoted

 WARN_ON_ONCE(ret);

    ret = 0;

    inode_dio_begin(inode);

This is expected and an indication of a problematic workload - which
may be triggered by a fuzzer.

If it's expected, why don't we kill the WARN_ON_ONCE()? I get it all
the time running xfstests as well.

Because when a user reports a data corruption, the only evidence we
have that they are running an app that does something stupid is this
warning in their syslogs.  Tracepoints are not useful for replacing
warnings about data corruption vectors being triggered.

It needs to be on by default, bu tI'm sure we can wrap it with
something like an xfs_alert_tag() type of construct so the tag can
be set in /proc/fs/xfs/panic_mask to suppress it if testers so
desire.

Cheers,

Dave.

-- 
Dave Chinner
david@fromorbit.com