Re: Kernel panic / list_add corruption when in nfsd4_run_cb_work

["J. Bruce Fields" <bfields@fieldses.org>]

On Mon, Oct 12, 2020 at 05:41:59PM +0200, Salvatore Bonaccorso wrote:
> Hi Bruce,
> 
> Thanks a lot for your reply, much appreciated.
> 
> On Mon, Oct 12, 2020 at 10:26:02AM -0400, J. Bruce Fields wrote:
> > On Sun, Oct 11, 2020 at 09:59:13AM +0200, Salvatore Bonaccorso wrote:
> > > Hi
> > > 
> > > On a system running 4.19.146-1 in Debian buster an issue got hit,
> > > while the server was under some slight load, but it does not seem
> > > easily reproducible, so asking if some more information can be
> > > provided to track/narrow this down. On the console the following was
> > > caught:
> > 
> > Worth checking git logs of fs/nfsd/nfs4state.c and
> > fs/nfsd/nfs4callback.c.  It might be
> > 2bbfed98a4d82ac4e7abfcd4eba40bddfc670b1d "nfsd: Fix races between
> > nfsd4_cb_release() and nfsd4_shutdown_callback()" ?
> 
> That might be possible. As it was not possible to simply trigger the
> issue, do you know if it is possible to simply reproduce the issue
> fixed in the above?

I don't have a reproducer.

--b.

> 
> 2bbfed98a4d8 ("nfsd: Fix races between nfsd4_cb_release() and
> nfsd4_shutdown_callback()") would be missing in the v4.19.y stable
> series (as it was in 5.5-rc1 but not backported to other stable
> versions).
> 
> Regards,
> Salvatore