* [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t
@ 2021-12-02 2:26 Eric Dumazet
2021-12-02 2:42 ` David Ahern
2021-12-02 12:20 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 4+ messages in thread
From: Eric Dumazet @ 2021-12-02 2:26 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski
Cc: netdev, Eric Dumazet, Eric Dumazet, David Ahern
From: Eric Dumazet <edumazet@google.com>
Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.
After the change, this is no longer the case, as free_fib_info_rcu()
runs after rcu grace period, without rtnl being held.
Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Ahern <dsahern@kernel.org>
---
include/net/ip_fib.h | 2 +-
include/net/netns/ipv4.h | 2 +-
net/ipv4/fib_frontend.c | 2 +-
net/ipv4/fib_rules.c | 4 ++--
net/ipv4/fib_semantics.c | 4 ++--
5 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index ab5348e57db1a627cbce2dededb2e9b754d1f2cd..3417ba2d27ad6a1b5612a8855d2788f10d9fdf25 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -438,7 +438,7 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
#ifdef CONFIG_IP_ROUTE_CLASSID
static inline int fib_num_tclassid_users(struct net *net)
{
- return net->ipv4.fib_num_tclassid_users;
+ return atomic_read(&net->ipv4.fib_num_tclassid_users);
}
#else
static inline int fib_num_tclassid_users(struct net *net)
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 2f65701a43c953bd3a9a9e3d491882cb7bb11859..6c5b2efc4f17d0d17be750d0c1a2e1d169ec063e 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -65,7 +65,7 @@ struct netns_ipv4 {
bool fib_has_custom_local_routes;
bool fib_offload_disabled;
#ifdef CONFIG_IP_ROUTE_CLASSID
- int fib_num_tclassid_users;
+ atomic_t fib_num_tclassid_users;
#endif
struct hlist_head *fib_table_hash;
struct sock *fibnl;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 9fe13e4f5d08a5cf9cd9ff15033b9f6e0dc9e492..4d61ddd8a0ecfc4cc47b4802eb5a573beb84ee44 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1582,7 +1582,7 @@ static int __net_init fib_net_init(struct net *net)
int error;
#ifdef CONFIG_IP_ROUTE_CLASSID
- net->ipv4.fib_num_tclassid_users = 0;
+ atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
#endif
error = ip_fib_net_init(net);
if (error < 0)
diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index 364ad3446b2f3c056ea5dafea1542e4d3306ddb6..d279cb8ac1584487885f66819634b421c01bf819 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -264,7 +264,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
if (tb[FRA_FLOW]) {
rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
if (rule4->tclassid)
- net->ipv4.fib_num_tclassid_users++;
+ atomic_inc(&net->ipv4.fib_num_tclassid_users);
}
#endif
@@ -296,7 +296,7 @@ static int fib4_rule_delete(struct fib_rule *rule)
#ifdef CONFIG_IP_ROUTE_CLASSID
if (((struct fib4_rule *)rule)->tclassid)
- net->ipv4.fib_num_tclassid_users--;
+ atomic_dec(&net->ipv4.fib_num_tclassid_users);
#endif
net->ipv4.fib_has_custom_rules = true;
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 3364cb9c67e018fea2b2e370046de5252581b996..fde7797b580694bb3924c5c6e9560cf04fd67387 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -220,7 +220,7 @@ void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
if (fib_nh->nh_tclassid)
- net->ipv4.fib_num_tclassid_users--;
+ atomic_dec(&net->ipv4.fib_num_tclassid_users);
#endif
fib_nh_common_release(&fib_nh->nh_common);
}
@@ -632,7 +632,7 @@ int fib_nh_init(struct net *net, struct fib_nh *nh,
#ifdef CONFIG_IP_ROUTE_CLASSID
nh->nh_tclassid = cfg->fc_flow;
if (nh->nh_tclassid)
- net->ipv4.fib_num_tclassid_users++;
+ atomic_inc(&net->ipv4.fib_num_tclassid_users);
#endif
#ifdef CONFIG_IP_ROUTE_MULTIPATH
nh->fib_nh_weight = nh_weight;
--
2.34.0.rc2.393.gf8c9666880-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t
2021-12-02 2:26 [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t Eric Dumazet
@ 2021-12-02 2:42 ` David Ahern
2021-12-02 2:58 ` Eric Dumazet
2021-12-02 12:20 ` patchwork-bot+netdevbpf
1 sibling, 1 reply; 4+ messages in thread
From: David Ahern @ 2021-12-02 2:42 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski
Cc: netdev, Eric Dumazet, David Ahern
On 12/1/21 7:26 PM, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
> changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.
>
> After the change, this is no longer the case, as free_fib_info_rcu()
> runs after rcu grace period, without rtnl being held.
>
> Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: David Ahern <dsahern@kernel.org>
> ---
> include/net/ip_fib.h | 2 +-
> include/net/netns/ipv4.h | 2 +-
> net/ipv4/fib_frontend.c | 2 +-
> net/ipv4/fib_rules.c | 4 ++--
> net/ipv4/fib_semantics.c | 4 ++--
> 5 files changed, 7 insertions(+), 7 deletions(-)
>
Thanks, Eric. Was this found by syzbot or code inspection?
Reviewed-by: David Ahern <dsahern@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t
2021-12-02 2:42 ` David Ahern
@ 2021-12-02 2:58 ` Eric Dumazet
0 siblings, 0 replies; 4+ messages in thread
From: Eric Dumazet @ 2021-12-02 2:58 UTC (permalink / raw)
To: David Ahern
Cc: Eric Dumazet, David S . Miller, Jakub Kicinski, netdev,
David Ahern
On Wed, Dec 1, 2021 at 6:42 PM David Ahern <dsahern@gmail.com> wrote:
>
> On 12/1/21 7:26 PM, Eric Dumazet wrote:
> > From: Eric Dumazet <edumazet@google.com>
> >
> > Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
> > changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.
> >
> > After the change, this is no longer the case, as free_fib_info_rcu()
> > runs after rcu grace period, without rtnl being held.
> >
> > Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
> > Cc: David Ahern <dsahern@kernel.org>
> > ---
> > include/net/ip_fib.h | 2 +-
> > include/net/netns/ipv4.h | 2 +-
> > net/ipv4/fib_frontend.c | 2 +-
> > net/ipv4/fib_rules.c | 4 ++--
> > net/ipv4/fib_semantics.c | 4 ++--
> > 5 files changed, 7 insertions(+), 7 deletions(-)
> >
>
> Thanks, Eric. Was this found by syzbot or code inspection?
>
Code inspection, while plumbing my dev_hold_track() and dev_put_track() helpers.
> Reviewed-by: David Ahern <dsahern@kernel.org>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t
2021-12-02 2:26 [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t Eric Dumazet
2021-12-02 2:42 ` David Ahern
@ 2021-12-02 12:20 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-12-02 12:20 UTC (permalink / raw)
To: Eric Dumazet; +Cc: davem, kuba, netdev, edumazet, dsahern
Hello:
This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:
On Wed, 1 Dec 2021 18:26:35 -0800 you wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
> changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.
>
> After the change, this is no longer the case, as free_fib_info_rcu()
> runs after rcu grace period, without rtnl being held.
>
> [...]
Here is the summary with links:
- [net] ipv4: convert fib_num_tclassid_users to atomic_t
https://git.kernel.org/netdev/net/c/213f5f8f31f1
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-12-02 2:26 [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t Eric Dumazet
2021-12-02 2:42 ` David Ahern
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2021-12-02 12:20 ` patchwork-bot+netdevbpf
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