Re: linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359

[Greg KH]

On Thu, Jul 22, 2021 at 01:36:02PM +0100, Matthew Wilcox wrote:
> On Thu, Jul 22, 2021 at 04:57:57PM +0800, Zhouyi Zhou wrote:
> > Thanks for reviewing,
> > 
> > What I have deduced from the dmesg  is:
> > In function do_swap_page,
> > after invoking
> > 3385        si = get_swap_device(entry); /* rcu_read_lock */
> > and before
> > 3561    out:
> > 3562        if (si)
> > 3563            put_swap_device(si);
> > The thread got scheduled out in
> > 3454        locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags);
> > 
> > I am only familiar with Linux RCU subsystem, hope mm people can solve our
> > confusions.
> 
> I don't understamd why you're still talking.  The problem is understood.
> You need to revert the unnecessary backport of 2799e77529c2 and
> 2efa33fc7f6e

Sorry for the delay, will go do so in a minute...

greg k-h