From 7a47281439ba00b11fc098f36695522184ce5a82 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Mon, 17 Feb 2020 12:12:09 +0200 Subject: [PATCH 1/4] net: sched: lock action when translating it to flow_action infra In order to remove dependency on rtnl lock, take action's tcfa_lock when constructing its representation as flow_action_entry structure. Refactor tcf_sample_get_group() to assume that caller holds tcf_lock and don't take it manually. This callback is only called from flow_action infra representation translator which now calls it with tcf_lock held, so this refactoring is necessary to prevent deadlock. Allocate memory with GFP_ATOMIC flag for ip_tunnel_info copy because tcf_tunnel_info_copy() is only called from flow_action representation infra code with tcf_lock spinlock taken. Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/tc_act/tc_tunnel_key.h | 2 +- net/sched/act_sample.c | 2 -- net/sched/cls_api.c | 17 +++++++++++------ 3 files changed, 12 insertions(+), 9 deletions(-) diff --git a/include/net/tc_act/tc_tunnel_key.h b/include/net/tc_act/tc_tunnel_key.h index 0689d9bcdf84..2b3df076e5b6 100644 --- a/include/net/tc_act/tc_tunnel_key.h +++ b/include/net/tc_act/tc_tunnel_key.h @@ -69,7 +69,7 @@ tcf_tunnel_info_copy(const struct tc_action *a) if (tun) { size_t tun_size = sizeof(*tun) + tun->options_len; struct ip_tunnel_info *tun_copy = kmemdup(tun, tun_size, - GFP_KERNEL); + GFP_ATOMIC); return tun_copy; } diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c index ce948c1e24dc..5e2df590bb58 100644 --- a/net/sched/act_sample.c +++ b/net/sched/act_sample.c @@ -267,14 +267,12 @@ tcf_sample_get_group(const struct tc_action *a, struct tcf_sample *s = to_sample(a); struct psample_group *group; - spin_lock_bh(&s->tcf_lock); group = rcu_dereference_protected(s->psample_group, lockdep_is_held(&s->tcf_lock)); if (group) { psample_group_take(group); *destructor = tcf_psample_group_put; } - spin_unlock_bh(&s->tcf_lock); return group; } diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index c2cdd0fc2e70..610505117780 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3435,7 +3435,7 @@ static void tcf_sample_get_group(struct flow_action_entry *entry, int tc_setup_flow_action(struct flow_action *flow_action, const struct tcf_exts *exts, bool rtnl_held) { - const struct tc_action *act; + struct tc_action *act; int i, j, k, err = 0; if (!exts) @@ -3449,6 +3449,7 @@ int tc_setup_flow_action(struct flow_action *flow_action, struct flow_action_entry *entry; entry = &flow_action->entries[j]; + spin_lock_bh(&act->tcfa_lock); if (is_tcf_gact_ok(act)) { entry->id = FLOW_ACTION_ACCEPT; } else if (is_tcf_gact_shot(act)) { @@ -3489,13 +3490,13 @@ int tc_setup_flow_action(struct flow_action *flow_action, break; default: err = -EOPNOTSUPP; - goto err_out; + goto err_out_locked; } } else if (is_tcf_tunnel_set(act)) { entry->id = FLOW_ACTION_TUNNEL_ENCAP; err = tcf_tunnel_encap_get_tunnel(entry, act); if (err) - goto err_out; + goto err_out_locked; } else if (is_tcf_tunnel_release(act)) { entry->id = FLOW_ACTION_TUNNEL_DECAP; } else if (is_tcf_pedit(act)) { @@ -3509,7 +3510,7 @@ int tc_setup_flow_action(struct flow_action *flow_action, break; default: err = -EOPNOTSUPP; - goto err_out; + goto err_out_locked; } entry->mangle.htype = tcf_pedit_htype(act, k); entry->mangle.mask = tcf_pedit_mask(act, k); @@ -3560,15 +3561,16 @@ int tc_setup_flow_action(struct flow_action *flow_action, entry->mpls_mangle.ttl = tcf_mpls_ttl(act); break; default: - goto err_out; + goto err_out_locked; } } else if (is_tcf_skbedit_ptype(act)) { entry->id = FLOW_ACTION_PTYPE; entry->ptype = tcf_skbedit_ptype(act); } else { err = -EOPNOTSUPP; - goto err_out; + goto err_out_locked; } + spin_unlock_bh(&act->tcfa_lock); if (!is_tcf_pedit(act)) j++; @@ -3582,6 +3584,9 @@ err_out: tc_cleanup_flow_action(flow_action); return err; +err_out_locked: + spin_unlock_bh(&act->tcfa_lock); + goto err_out; } EXPORT_SYMBOL(tc_setup_flow_action); From 487e9589cc0ebebde4d1c4764aab271e5680a6b6 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Mon, 17 Feb 2020 12:12:10 +0200 Subject: [PATCH 2/4] net: sched: refactor police action helpers to require tcf_lock In order to remove rtnl lock dependency from flow_action representation translator, change rcu_dereference_bh_rtnl() to rcu_dereference_protected() in police action helpers that provide external access to rate and burst values. This is safe to do because the functions are not called from anywhere else outside flow_action infrastructure which was modified to obtain tcf_lock when accessing action data in one of previous patches in the series. Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/tc_act/tc_police.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/net/tc_act/tc_police.h b/include/net/tc_act/tc_police.h index cfdc7cb82cad..f098ad4424be 100644 --- a/include/net/tc_act/tc_police.h +++ b/include/net/tc_act/tc_police.h @@ -54,7 +54,8 @@ static inline u64 tcf_police_rate_bytes_ps(const struct tc_action *act) struct tcf_police *police = to_police(act); struct tcf_police_params *params; - params = rcu_dereference_bh_rtnl(police->params); + params = rcu_dereference_protected(police->params, + lockdep_is_held(&police->tcf_lock)); return params->rate.rate_bytes_ps; } @@ -63,7 +64,8 @@ static inline s64 tcf_police_tcfp_burst(const struct tc_action *act) struct tcf_police *police = to_police(act); struct tcf_police_params *params; - params = rcu_dereference_bh_rtnl(police->params); + params = rcu_dereference_protected(police->params, + lockdep_is_held(&police->tcf_lock)); return params->tcfp_burst; } From 107f2d50916500985b9fffd7c77d8c14809f9802 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Mon, 17 Feb 2020 12:12:11 +0200 Subject: [PATCH 3/4] net: sched: refactor ct action helpers to require tcf_lock In order to remove rtnl lock dependency from flow_action representation translator, change rtnl_dereference() to rcu_dereference_protected() in ct action helpers that provide external access to zone and action values. This is safe to do because the functions are not called from anywhere else outside flow_action infrastructure which was modified to obtain tcf_lock when accessing action data in one of previous patches in the series. Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/tc_act/tc_ct.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/net/tc_act/tc_ct.h b/include/net/tc_act/tc_ct.h index bdc20ab3b88d..a8b156402873 100644 --- a/include/net/tc_act/tc_ct.h +++ b/include/net/tc_act/tc_ct.h @@ -33,8 +33,10 @@ struct tcf_ct { }; #define to_ct(a) ((struct tcf_ct *)a) -#define to_ct_params(a) ((struct tcf_ct_params *) \ - rtnl_dereference((to_ct(a)->params))) +#define to_ct_params(a) \ + ((struct tcf_ct_params *) \ + rcu_dereference_protected(to_ct(a)->params, \ + lockdep_is_held(&a->tcfa_lock))) static inline uint16_t tcf_ct_zone(const struct tc_action *a) { From b15e7a6e8d31d6abe2d98929d60ad3a0e6ae4de1 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Mon, 17 Feb 2020 12:12:12 +0200 Subject: [PATCH 4/4] net: sched: don't take rtnl lock during flow_action setup Refactor tc_setup_flow_action() function not to use rtnl lock and remove 'rtnl_held' argument that is no longer needed. Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/pkt_cls.h | 2 +- net/sched/cls_api.c | 8 +------- net/sched/cls_flower.c | 6 ++---- net/sched/cls_matchall.c | 4 ++-- 4 files changed, 6 insertions(+), 14 deletions(-) diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index a972244ab193..53946b509b51 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -509,7 +509,7 @@ tcf_match_indev(struct sk_buff *skb, int ifindex) } int tc_setup_flow_action(struct flow_action *flow_action, - const struct tcf_exts *exts, bool rtnl_held); + const struct tcf_exts *exts); void tc_cleanup_flow_action(struct flow_action *flow_action); int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type, diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 610505117780..13c33eaf1ca1 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3433,7 +3433,7 @@ static void tcf_sample_get_group(struct flow_action_entry *entry, } int tc_setup_flow_action(struct flow_action *flow_action, - const struct tcf_exts *exts, bool rtnl_held) + const struct tcf_exts *exts) { struct tc_action *act; int i, j, k, err = 0; @@ -3441,9 +3441,6 @@ int tc_setup_flow_action(struct flow_action *flow_action, if (!exts) return 0; - if (!rtnl_held) - rtnl_lock(); - j = 0; tcf_exts_for_each_action(i, act, exts) { struct flow_action_entry *entry; @@ -3577,9 +3574,6 @@ int tc_setup_flow_action(struct flow_action *flow_action, } err_out: - if (!rtnl_held) - rtnl_unlock(); - if (err) tc_cleanup_flow_action(flow_action); diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 7e54d2ab5254..726fc9c5910f 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -449,8 +449,7 @@ static int fl_hw_replace_filter(struct tcf_proto *tp, cls_flower.rule->match.key = &f->mkey; cls_flower.classid = f->res.classid; - err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts, - rtnl_held); + err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts); if (err) { kfree(cls_flower.rule); if (skip_sw) { @@ -2000,8 +1999,7 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb, cls_flower.rule->match.mask = &f->mask->key; cls_flower.rule->match.key = &f->mkey; - err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts, - true); + err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts); if (err) { kfree(cls_flower.rule); if (tc_skip_sw(f->flags)) { diff --git a/net/sched/cls_matchall.c b/net/sched/cls_matchall.c index 610a0b728161..a34b36adb9b7 100644 --- a/net/sched/cls_matchall.c +++ b/net/sched/cls_matchall.c @@ -97,7 +97,7 @@ static int mall_replace_hw_filter(struct tcf_proto *tp, cls_mall.command = TC_CLSMATCHALL_REPLACE; cls_mall.cookie = cookie; - err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts, true); + err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts); if (err) { kfree(cls_mall.rule); mall_destroy_hw_filter(tp, head, cookie, NULL); @@ -302,7 +302,7 @@ static int mall_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb, TC_CLSMATCHALL_REPLACE : TC_CLSMATCHALL_DESTROY; cls_mall.cookie = (unsigned long)head; - err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts, true); + err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts); if (err) { kfree(cls_mall.rule); if (add && tc_skip_sw(head->flags)) {