Commit 51e398e8 authored Oct 06, 2017 by Wei Wang Committed by David S. Miller Oct 07, 2017

ipv6: don't release rt->rt6i_pcpu memory during rt6_release()



After rwlock is replaced with rcu and spinlock, route lookup can happen
simultanously with route deletion.
This patch removes the call to free_percpu(rt->rt6i_pcpu) from
rt6_release() to avoid the race condition between rt6_release() and
rt6_get_pcpu_route(). And as free_percpu(rt->rt6i_pcpu) is already
called in ip6_dst_destroy() after the rcu grace period, it is safe to do
this change.

Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent a94b9367

net/ipv6/ip6_fib.c

+0 −3

Original line number	Original line	Diff line number	Diff line
	@@ -190,9 +190,6 @@ void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
	*ppcpu_rt = NULL;		*ppcpu_rt = NULL;
	}		}
	}		}

	free_percpu(non_pcpu_rt->rt6i_pcpu);
	non_pcpu_rt->rt6i_pcpu = NULL;
	}		}
	EXPORT_SYMBOL_GPL(rt6_free_pcpu);		EXPORT_SYMBOL_GPL(rt6_free_pcpu);