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Message-ID: <20260121131954.2710459-8-p@1g4.org>
Date: Wed, 21 Jan 2026 13:21:03 +0000
From: Paul Moses <p@....org>
To: netdev@...r.kernel.org
Cc: Jamal Hadi Salim <jhs@...atatu.com>, Cong Wang <xiyou.wangcong@...il.com>, Jiri Pirko <jiri@...nulli.us>, "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, linux-kernel@...r.kernel.org, Paul Moses <p@....org>, stable@...r.kernel.org
Subject: [PATCH net v3 7/7] net/sched: act_gate: guard NULL params in accessors
Guard NULL params in accessors/dump/timer paths to avoid crashes during
teardown or failed initialization. Other actions already guard params before
RCU cleanup (act_pedit, commit 52cf89f78c01bf; act_vlan, commits 4c5b9d9642c859
and 1edf8abe04090c), so act_gate should tolerate NULL in reader paths too.
Fixes: a51c328df310 ("net: qos: introduce a gate control flow action")
Signed-off-by: Paul Moses <p@....org>
Cc: stable@...r.kernel.org
---
include/net/tc_act/tc_gate.h | 30 ++++++++++++++++++++----------
net/sched/act_gate.c | 13 ++++++++++++-
2 files changed, 32 insertions(+), 11 deletions(-)
diff --git a/include/net/tc_act/tc_gate.h b/include/net/tc_act/tc_gate.h
index 9587d9e9fa38f..8c3309b0dd779 100644
--- a/include/net/tc_act/tc_gate.h
+++ b/include/net/tc_act/tc_gate.h
@@ -54,12 +54,13 @@ struct tcf_gate {
static inline s32 tcf_gate_prio(const struct tc_action *a)
{
- s32 tcfg_prio;
+ s32 tcfg_prio = 0;
struct tcf_gate_params *p;
rcu_read_lock();
p = rcu_dereference(to_gate(a)->param);
- tcfg_prio = p->tcfg_priority;
+ if (p)
+ tcfg_prio = p->tcfg_priority;
rcu_read_unlock();
return tcfg_prio;
@@ -67,12 +68,13 @@ static inline s32 tcf_gate_prio(const struct tc_action *a)
static inline u64 tcf_gate_basetime(const struct tc_action *a)
{
- u64 tcfg_basetime;
+ u64 tcfg_basetime = 0;
struct tcf_gate_params *p;
rcu_read_lock();
p = rcu_dereference(to_gate(a)->param);
- tcfg_basetime = p->tcfg_basetime;
+ if (p)
+ tcfg_basetime = p->tcfg_basetime;
rcu_read_unlock();
return tcfg_basetime;
@@ -80,12 +82,13 @@ static inline u64 tcf_gate_basetime(const struct tc_action *a)
static inline u64 tcf_gate_cycletime(const struct tc_action *a)
{
- u64 tcfg_cycletime;
+ u64 tcfg_cycletime = 0;
struct tcf_gate_params *p;
rcu_read_lock();
p = rcu_dereference(to_gate(a)->param);
- tcfg_cycletime = p->tcfg_cycletime;
+ if (p)
+ tcfg_cycletime = p->tcfg_cycletime;
rcu_read_unlock();
return tcfg_cycletime;
@@ -93,12 +96,13 @@ static inline u64 tcf_gate_cycletime(const struct tc_action *a)
static inline u64 tcf_gate_cycletimeext(const struct tc_action *a)
{
- u64 tcfg_cycletimeext;
+ u64 tcfg_cycletimeext = 0;
struct tcf_gate_params *p;
rcu_read_lock();
p = rcu_dereference(to_gate(a)->param);
- tcfg_cycletimeext = p->tcfg_cycletime_ext;
+ if (p)
+ tcfg_cycletimeext = p->tcfg_cycletime_ext;
rcu_read_unlock();
return tcfg_cycletimeext;
@@ -106,12 +110,13 @@ static inline u64 tcf_gate_cycletimeext(const struct tc_action *a)
static inline u32 tcf_gate_num_entries(const struct tc_action *a)
{
- u32 num_entries;
+ u32 num_entries = 0;
struct tcf_gate_params *p;
rcu_read_lock();
p = rcu_dereference(to_gate(a)->param);
- num_entries = p->num_entries;
+ if (p)
+ num_entries = p->num_entries;
rcu_read_unlock();
return num_entries;
@@ -128,6 +133,11 @@ static inline struct action_gate_entry
rcu_read_lock();
p = rcu_dereference(to_gate(a)->param);
+ if (!p) {
+ rcu_read_unlock();
+ return NULL;
+ }
+
num_entries = p->num_entries;
list_for_each_entry(entry, &p->entries, list)
diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c
index e4134b9a4a314..65b53cbf37e67 100644
--- a/net/sched/act_gate.c
+++ b/net/sched/act_gate.c
@@ -82,7 +82,11 @@ static enum hrtimer_restart gate_timer_func(struct hrtimer *timer)
p = rcu_dereference_protected(gact->param,
lockdep_is_held(&gact->tcf_lock));
+ if (!p)
+ goto out_unlock;
next = gact->next_entry;
+ if (!next)
+ goto out_unlock;
/* cycle start, clear pending bit, clear total octets */
gact->current_gate_status = next->gate_state ? GATE_ACT_GATE_OPEN : 0;
@@ -119,6 +123,11 @@ static enum hrtimer_restart gate_timer_func(struct hrtimer *timer)
spin_unlock(&gact->tcf_lock);
return HRTIMER_RESTART;
+
+out_unlock:
+ spin_unlock(&gact->tcf_lock);
+
+ return HRTIMER_NORESTART;
}
TC_INDIRECT_SCOPE int tcf_gate_act(struct sk_buff *skb,
@@ -584,8 +593,8 @@ static void tcf_gate_cleanup(struct tc_action *a)
struct tcf_gate *gact = to_gate(a);
struct tcf_gate_params *p;
- p = rcu_replace_pointer(gact->param, NULL, lockdep_rtnl_is_held());
hrtimer_cancel(&gact->hitimer);
+ p = rcu_replace_pointer(gact->param, NULL, lockdep_rtnl_is_held());
if (p)
call_rcu(&p->rcu, tcf_gate_params_free_rcu);
}
@@ -643,6 +652,8 @@ static int tcf_gate_dump(struct sk_buff *skb, struct tc_action *a,
rcu_read_lock();
p = rcu_dereference(gact->param);
+ if (!p)
+ goto nla_put_failure_rcu;
if (nla_put_u64_64bit(skb, TCA_GATE_BASE_TIME,
p->tcfg_basetime, TCA_GATE_PAD))
--
2.52.GIT
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