From: Florian Westphal <fw@strlen.de>
To: Vakul Garg <vakul.garg@nxp.com>
Cc: Florian Westphal <fw@strlen.de>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: Help needed - Kernel lockup while running ipsec
Date: Tue, 20 Aug 2019 11:23:03 +0200 [thread overview]
Message-ID: <20190820092303.GM2588@breakpoint.cc> (raw)
In-Reply-To: <DB7PR04MB4620C6E770C97AB14A04A1D98BAB0@DB7PR04MB4620.eurprd04.prod.outlook.com>
Vakul Garg <vakul.garg@nxp.com> wrote:
> > > With kernel 4.14.122, I am getting a kernel softlockup while running single
> > static ipsec tunnel.
> > > The problem reproduces mostly after running 8-10 hours of ipsec encap
> > test (on my dual core arm board).
> > >
> > > I found that in function xfrm_policy_lookup_bytype(), the policy in variable
> > 'ret' shows refcnt=0 under problem situation.
> > > This creates an infinite loop in xfrm_policy_lookup_bytype() and hence the
> > lockup.
> > >
> > > Can some body please provide me pointers about 'refcnt'?
> > > Is it legitimate for 'refcnt' to become '0'? Under what condition can it
> > become '0'?
> >
> > Yes, when policy is destroyed and the last user calls
> > xfrm_pol_put() which will invoke call_rcu to free the structure.
>
> It seems that policy reference count never gets decremented during packet ipsec encap.
> It is getting incremented for every frame that hits the policy.
> In setkey -DP output, I see refcnt to be wrapping around after '0'.
Thats a bug. Does this affect 4.14 only or does this happen on current
tree as well?
next prev parent reply other threads:[~2019-08-20 9:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 12:55 Help needed - Kernel lockup while running ipsec Vakul Garg
2019-08-19 17:38 ` Florian Westphal
2019-08-20 9:10 ` Vakul Garg
2019-08-20 9:23 ` Florian Westphal [this message]
2019-08-20 9:26 ` Vakul Garg
2019-08-20 9:30 ` Vakul Garg
2019-08-20 9:38 ` Florian Westphal
2019-08-20 9:52 ` Vakul Garg
2019-08-20 10:38 ` Vakul Garg
2019-08-21 7:37 ` Vakul Garg
2019-08-21 16:11 ` Florian Westphal
2019-08-22 10:23 ` Vakul Garg
2019-08-22 11:21 ` [PATCH 4.14.y stable] xfrm: policy: remove pcpu policy cache Florian Westphal
2019-08-22 13:09 ` Greg KH
2019-08-22 13:37 ` Florian Westphal
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