> -----邮件原件----- > 发件人: Eric Dumazet [mailto:eric.dumazet@xxxxxxxxx] > 发送时间: 2019年2月25日 23:56 > 收件人: Li,Rongqing <lirongqing@xxxxxxxxx>; netfilter-devel@xxxxxxxxxxxxxxx > 主题: Re: 答复: 答复: [PATCH] netfilter: force access of RCU protected data in > nft_update_chain_stats > > > > On 02/24/2019 10:00 PM, Li,Rongqing wrote: > > > > > >> -----邮件原件----- > >> 发件人: Eric Dumazet [mailto:eric.dumazet@xxxxxxxxx] > >> 发送时间: 2019年2月25日 12:11 > >> 收件人: Li,Rongqing <lirongqing@xxxxxxxxx>; > >> netfilter-devel@xxxxxxxxxxxxxxx > >> 主题: Re: 答复: [PATCH] netfilter: force access of RCU protected data in > >> nft_update_chain_stats > >> > >> > >> > >> On 02/24/2019 08:03 PM, Li,Rongqing wrote: > >>> > >>> > >>>> -----邮件原件----- > >>>> 发件人: Eric Dumazet [mailto:eric.dumazet@xxxxxxxxx] > >>>> 发送时间: 2019年2月25日 11:50 > >>>> 收件人: Li,Rongqing <lirongqing@xxxxxxxxx>; > >>>> netfilter-devel@xxxxxxxxxxxxxxx > >>>> 主题: Re: [PATCH] netfilter: force access of RCU protected data in > >>>> nft_update_chain_stats > >>>> > >>>> > >>>> > > > > > > [RFC] netfilter: check the result of dereferencing > > base_chain->stats > > > > check the result of dereferencing base_chain->stats, instead of > > result of this_cpu_ptr > > > > base_chain->stats maybe change to NULL when a chain is updated, > > a NULL counter can be attached > > > > and we do not need to check returning of this_cpu_ptr since > > base_chain->stats is allocated by percpu allocator if it is > > non-NULL, this_cpu_ptr returns a valid value > > > > diff --git a/net/netfilter/nf_tables_core.c > > b/net/netfilter/nf_tables_core.c index 2a00aef7b6d4..ed8a382d1012 > > 100644 > > --- a/net/netfilter/nf_tables_core.c > > +++ b/net/netfilter/nf_tables_core.c > > @@ -98,15 +98,16 @@ static noinline void nft_update_chain_stats(const > struct nft_chain *chain, > > const struct > nft_pktinfo > > *pkt) { > > struct nft_base_chain *base_chain; > > - struct nft_stats *stats; > > + struct nft_stats *stats, *pstats; > > OK but then make sure to add proper sparse annotations ( aka __percpu ) > I test this and found , there is always sparse error whether add __percpu or not Like: struct nft_stats __percpu *pstats; pstats = rcu_dereference(base_chain->stats); error: incompatible types in comparison expression (different address spaces) -RongQing
