From: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
To: Guillaume Nault <gnault@redhat.com>
Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Shuah Khan <shuah@kernel.org>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: POSSIBLE BUG: selftests/net/fcnal-test.sh: [FAIL] in vrf "bind - ns-B IPv6 LLA" test
Date: Tue, 6 Jun 2023 15:57:35 +0200 [thread overview]
Message-ID: <60f78eaa-ace7-c27d-8e45-4777ecf3faa2@alu.unizg.hr> (raw)
In-Reply-To: <ZH84zGEODT97TEXG@debian>
On 6/6/23 15:46, Guillaume Nault wrote:
> On Tue, Jun 06, 2023 at 08:24:54AM +0200, Mirsad Goran Todorovac wrote:
>> On 5/31/23 20:11, Guillaume Nault wrote:
>>> I believe this condition should be relaxed to allow the case where
>>> ->sk_bound_dev_if is oif's master device (and maybe there are other
>>> VRF cases to also consider).
>>
>> I've tried something like this, but something makes the kernel stuck
>> here:
>>
>> TEST: ping out, blocked by route - ns-B loopback IPv6 [ OK ]
>> TEST: ping out, device bind, blocked by route - ns-B loopback IPv6 [ OK ]
>> TEST: ping in, blocked by route - ns-A loopback IPv6 [ OK ]
>> TEST: ping out, unreachable route - ns-B loopback IPv6 [ OK ]
>> TEST: ping out, device bind, unreachable route - ns-B loopback IPv6 [ OK ]
>>
>> #################################################################
>> With VRF
>>
>> [hanged process and kernel won't shutdown]
>>
>> The code is:
>>
>> ---
>> net/ipv6/ping.c | 12 +++++++++++-
>> 1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
>> index c4835dbdfcff..81293e902293 100644
>> --- a/net/ipv6/ping.c
>> +++ b/net/ipv6/ping.c
>> @@ -73,6 +73,9 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
>> struct rt6_info *rt;
>> struct pingfakehdr pfh;
>> struct ipcm6_cookie ipc6;
>> + struct net *net = sock_net(sk);
>> + struct net_device *dev = NULL;
>> + struct net_device *mdev = NULL;
>> err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
>> sizeof(user_icmph));
>> @@ -111,10 +114,17 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
>> else if (!oif)
>> oif = np->ucast_oif;
>> + if (oif) {
>> + dev = dev_get_by_index(net, oif);
>> + mdev = netdev_master_upper_dev_get(dev);
>> + }
>> +
>> addr_type = ipv6_addr_type(daddr);
>> if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
>> (addr_type & IPV6_ADDR_MAPPED) ||
>> - (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
>> + (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&
>> + !(mdev && sk->sk_bound_dev_if &&
>> + mdev != dev_get_by_index(net, sk->sk_bound_dev_if))))
>> return -EINVAL;
>> ipcm6_init_sk(&ipc6, np);
>>
>> I am obviously doing something very stupid.
>
> The problem is that dev_get_by_index() holds a reference on 'dev' which
> your code never releases. Also netdev_master_upper_dev_get() needs rtnl
> protection. These should have generated some kernel oops.
>
> You can try this instead:
>
> -------- >8 --------
>
> diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
> index c4835dbdfcff..f804c11e2146 100644
> --- a/net/ipv6/ping.c
> +++ b/net/ipv6/ping.c
> @@ -114,7 +114,8 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
> addr_type = ipv6_addr_type(daddr);
> if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
> (addr_type & IPV6_ADDR_MAPPED) ||
> - (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
> + (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&
> + l3mdev_master_ifindex_by_index(sock_net(sk), oif) != sk->sk_bound_dev_if))
> return -EINVAL;
>
> ipcm6_init_sk(&ipc6, np);
Yes, I stupidly forgot that.
I came across a fixed version:
------
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index c4835dbdfcff..c1d81c49b775 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -73,6 +73,10 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
struct rt6_info *rt;
struct pingfakehdr pfh;
struct ipcm6_cookie ipc6;
+ struct net *net = sock_net(sk);
+ struct net_device *dev = NULL;
+ struct net_device *mdev = NULL;
+ struct net_device *bdev = NULL;
err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
sizeof(user_icmph));
@@ -111,10 +115,26 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
else if (!oif)
oif = np->ucast_oif;
+ if (oif) {
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(net, oif);
+ rcu_read_unlock();
+ rtnl_lock();
+ mdev = netdev_master_upper_dev_get(dev);
+ rtnl_unlock();
+ }
+
+ if (sk->sk_bound_dev_if) {
+ rcu_read_lock();
+ bdev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
+ rcu_read_unlock();
+ }
+
addr_type = ipv6_addr_type(daddr);
if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
(addr_type & IPV6_ADDR_MAPPED) ||
- (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
+ (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&
+ !(mdev && sk->sk_bound_dev_if && bdev && mdev == bdev)))
return -EINVAL;
ipcm6_init_sk(&ipc6, np);
However, this works by the test (888 passed) but your two liner is obviously
better :-)
Best regards,
Mirsad
--
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
next prev parent reply other threads:[~2023-06-06 13:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-24 12:17 POSSIBLE BUG: selftests/net/fcnal-test.sh: [FAIL] in vrf "bind - ns-B IPv6 LLA" test Mirsad Todorovac
2023-05-31 18:11 ` Guillaume Nault
2023-06-02 12:35 ` Mirsad Goran Todorovac
2023-06-06 6:24 ` Mirsad Goran Todorovac
2023-06-06 13:46 ` Guillaume Nault
2023-06-06 13:57 ` Mirsad Todorovac [this message]
2023-06-06 14:11 ` Guillaume Nault
2023-06-06 14:28 ` Mirsad Todorovac
2023-06-06 18:50 ` Guillaume Nault
2023-06-06 19:17 ` Mirsad Goran Todorovac
2023-06-06 19:27 ` Guillaume Nault
2023-06-06 18:07 ` POSSIBLE BUG: selftests/net/fcnal-test.sh: [FAIL][FIX TESTED] " Mirsad Goran Todorovac
2023-06-06 18:57 ` Guillaume Nault
2023-06-06 22:04 ` Mirsad Goran Todorovac
2023-06-07 16:51 ` Guillaume Nault
2023-06-08 5:37 ` Mirsad Goran Todorovac
2023-06-09 16:13 ` Guillaume Nault
2023-06-10 18:04 ` Mirsad Goran Todorovac
2023-06-14 8:47 ` Guillaume Nault
2023-06-15 20:10 ` Mirsad Goran Todorovac
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