Vakul Garg <vakul.g...@nxp.com> wrote: > > > > -----Original Message----- > > From: Florian Westphal <f...@strlen.de> > > Sent: Tuesday, August 20, 2019 2:53 PM > > To: Vakul Garg <vakul.g...@nxp.com> > > Cc: Florian Westphal <f...@strlen.de>; netdev@vger.kernel.org > > Subject: Re: Help needed - Kernel lockup while running ipsec > > > > Vakul Garg <vakul.g...@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? > > I am yet to try it on 4.19. > Can you help me with the right fix? Which part of code should it get > decremented? > I am not conversant with xfrm code.
Normally policy reference counts get decremented when the skb is free'd, via dst destruction (xfrm_dst_destroy()). Do you see a dst leak as well?
