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Date:   Mon, 12 Sep 2022 12:15:08 +0200
From:   Eugeniu Rosca <erosca@de.adit-jv.com>
To:     "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
CC:     Eugeniu Rosca <erosca@de.adit-jv.com>,
        Trond Myklebust <trondmy@hammerspace.com>,
        "neilb@suse.de" <neilb@suse.de>,
        "mrodin@de.adit-jv.com" <mrodin@de.adit-jv.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "roscaeugeniu@gmail.com" <roscaeugeniu@gmail.com>
Subject: Re: [PATCH 4.14 022/284] SUNRPC: avoid race between mod_timer() and
 del_timer_sync()
Message-ID: <20220912101508.GA5500@lxhi-065>
References: <20220418121210.689577360@linuxfoundation.org>
 <20220418121211.327937970@linuxfoundation.org>
 <20220907142548.GA9975@lxhi-065>
 <166259870333.30452.4204968221881228505@noble.neil.brown.name>
 <f575eeb3000330d9194c6256ad6063bc58f996c7.camel@hammerspace.com>
 <20220908120931.GA3480@lxhi-065>
 <Yx107owrRwmIc7pX@kroah.com>
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Hello Greg,

On So, Sep 11, 2022 at 07:41:02 +0200, gregkh@linuxfoundation.org wrote:
> On Thu, Sep 08, 2022 at 02:09:31PM +0200, Eugeniu Rosca wrote:

[..]

> > Your proposal [*] seems to resolve the issue for me.
> > 
> > Any chance to get a stable patch, to which I will gladly provide
> > the Reviewed-by/Tested-by signatures?
> > 
> > > > 
> > > > NeilBrown
> > > > 
> > 
> > [*] diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
> > index e7d55d63d4f1..7f9b94acf597 100644
> > --- a/net/sunrpc/xprt.c
> > +++ b/net/sunrpc/xprt.c
> > @@ -1525,9 +1525,9 @@ static void xprt_destroy(struct rpc_xprt *xprt)
> >  	 * is cleared.  We use ->transport_lock to ensure the mod_timer()
> >  	 * can only run *before* del_time_sync(), never after.
> >  	 */
> > -	spin_lock(&xprt->transport_lock);
> > +	spin_lock_bh(&xprt->transport_lock);
> >  	del_timer_sync(&xprt->timer);
> > -	spin_unlock(&xprt->transport_lock);
> > +	spin_unlock_bh(&xprt->transport_lock);
> >  
> >  	/*
> >  	 * Destroy sockets etc from the system workqueue so they can
> > 
> 
> Can you just turn this into a proper patch that we can apply to the
> needed stable tree(s)?

It has been kindly provided by Neil Brown in
https://lore.kernel.org/lkml/166293725263.30452.1720462103844620549@noble.neil.brown.name/

Best Regards,
Eugeniu Rosca