From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Buslov Subject: Re: [PATCH 09/14] net: sched: don't release reference on action overwrite Date: Wed, 16 May 2018 10:47:32 +0300 Message-ID: References: <1526308035-12484-1-git-send-email-vladbu@mellanox.com> <1526308035-12484-10-git-send-email-vladbu@mellanox.com> <20180516074332.GB1972@nanopsycho> Mime-Version: 1.0 Content-Type: text/plain Cc: netdev@vger.kernel.org, davem@davemloft.net, jhs@mojatatu.com, xiyou.wangcong@gmail.com, pablo@netfilter.org, kadlec@blackhole.kfki.hu, fw@strlen.de, ast@kernel.org, daniel@iogearbox.net, edumazet@google.com, keescook@chromium.org, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, kliteyn@mellanox.com To: Jiri Pirko Return-path: In-reply-to: <20180516074332.GB1972@nanopsycho> Sender: linux-kernel-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org On Wed 16 May 2018 at 07:43, Jiri Pirko wrote: > Mon, May 14, 2018 at 04:27:10PM CEST, vladbu@mellanox.com wrote: >>Return from action init function with reference to action taken, >>even when overwriting existing action. >> >>Action init API initializes its fourth argument (pointer to pointer to >>tc action) to either existing action with same index or newly created >>action. In case of existing index(and bind argument is zero), init >>function returns without incrementing action reference counter. Caller >>of action init then proceeds working with action without actually >>holding reference to it. This means that action could be deleted >>concurrently. To prevent such scenario this patch changes action init > > Be imperative to the codebase in the patch description. > > >>behavior to always take reference to action before returning >>successfully. > > Where's the balance? Who does the release instead? I'm probably missing > something. I've resplit these patches for V2 to always do take/release in same patch. > >> >>Signed-off-by: Vlad Buslov >>--- >> net/sched/act_bpf.c | 8 ++++---- >> net/sched/act_connmark.c | 5 +++-- >> net/sched/act_csum.c | 8 ++++---- >> net/sched/act_gact.c | 5 +++-- >> net/sched/act_ife.c | 12 +++++------- >> net/sched/act_ipt.c | 5 +++-- >> net/sched/act_mirred.c | 5 ++--- >> net/sched/act_nat.c | 5 +++-- >> net/sched/act_pedit.c | 5 +++-- >> net/sched/act_police.c | 8 +++----- >> net/sched/act_sample.c | 8 +++----- >> net/sched/act_simple.c | 5 +++-- >> net/sched/act_skbedit.c | 5 +++-- >> net/sched/act_skbmod.c | 8 +++----- >> net/sched/act_tunnel_key.c | 8 +++----- >> net/sched/act_vlan.c | 8 +++----- >> 16 files changed, 51 insertions(+), 57 deletions(-) >> >>diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c >>index 5d95c43..5554bf7 100644 >>--- a/net/sched/act_bpf.c >>+++ b/net/sched/act_bpf.c >>@@ -311,9 +311,10 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla, >> if (bind) >> return 0; >> >>- tcf_idr_release(*act, bind); >>- if (!replace) >>+ if (!replace) { >>+ tcf_idr_release(*act, bind); >> return -EEXIST; >>+ } >> } >> >> is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; > > [...]