* [PATCH 00/12] l2tp bugfix patchset
@ 2013-03-19 16:11 Tom Parkin
2013-03-19 16:11 ` [PATCH 01/12] udp: add encap_destroy callback Tom Parkin
` (12 more replies)
0 siblings, 13 replies; 14+ messages in thread
From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw)
To: netdev; +Cc: Tom Parkin
This l2tp bugfix patchset addresses a number of issues.
The first five patches in the series prevent l2tp sessions pinning an l2tp
tunnel open. This occurs because the l2tp tunnel is torn down in the tunnel
socket destructor, but each session holds a tunnel socket reference which
prevents tunnels with sessions being deleted. The solution I've implemented
here involves adding a .destroy hook to udp code, as discussed previously on
netdev[1].
The subsequent seven patches address futher bugs exposed by fixing the problem
above, or exposed through stress testing the implementation above. Patch 11
(avoid deadlock in l2tp stats update) isn't directly related to tunnel/session
lifetimes, but it does prevent deadlocks on i386 kernels running on 64 bit
hardware.
This patchset has been tested on 32 and 64 bit preempt/non-preempt kernels,
using iproute2, openl2tp, and custom-made stress test code.
[1] http://comments.gmane.org/gmane.linux.network/259169
Tom Parkin (12):
udp: add encap_destroy callback
l2tp: add udp encap socket destroy handler
l2tp: export l2tp_tunnel_closeall
l2tp: close sessions in ip socket destroy callback
l2tp: close sessions before initiating tunnel delete
l2tp: take a reference for kernel sockets in l2tp_tunnel_sock_lookup
l2tp: don't BUG_ON sk_socket being NULL
l2tp: add session reorder queue purge function to core
l2tp: purge session reorder queue on delete
l2tp: push all ppp pseudowire shutdown through .release handler
l2tp: avoid deadlock in l2tp stats update
l2tp: unhash l2tp sessions on delete, not on free
include/linux/udp.h | 1 +
net/ipv4/udp.c | 7 ++
net/ipv6/udp.c | 8 ++
net/l2tp/l2tp_core.c | 206 +++++++++++++++++++++++------------------------
net/l2tp/l2tp_core.h | 22 ++---
net/l2tp/l2tp_debugfs.c | 28 +++----
net/l2tp/l2tp_ip.c | 6 ++
net/l2tp/l2tp_ip6.c | 7 ++
net/l2tp/l2tp_netlink.c | 72 +++++++----------
net/l2tp/l2tp_ppp.c | 111 +++++++++----------------
10 files changed, 220 insertions(+), 248 deletions(-)
--
1.7.9.5
^ permalink raw reply [flat|nested] 14+ messages in thread* [PATCH 01/12] udp: add encap_destroy callback 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 02/12] l2tp: add udp encap socket destroy handler Tom Parkin ` (11 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman Users of udp encapsulation currently have an encap_rcv callback which they can use to hook into the udp receive path. In situations where a encapsulation user allocates resources associated with a udp encap socket, it may be convenient to be able to also hook the proto .destroy operation. For example, if an encap user holds a reference to the udp socket, the destroy hook might be used to relinquish this reference. This patch adds a socket destroy hook into udp, which is set and enabled in the same way as the existing encap_rcv hook. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- include/linux/udp.h | 1 + net/ipv4/udp.c | 7 +++++++ net/ipv6/udp.c | 8 ++++++++ 3 files changed, 16 insertions(+) diff --git a/include/linux/udp.h b/include/linux/udp.h index 9d81de1..42278bb 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -68,6 +68,7 @@ struct udp_sock { * For encapsulation sockets. */ int (*encap_rcv)(struct sock *sk, struct sk_buff *skb); + void (*encap_destroy)(struct sock *sk); }; static inline struct udp_sock *udp_sk(const struct sock *sk) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 41760e0..7117d14 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1762,9 +1762,16 @@ int udp_rcv(struct sk_buff *skb) void udp_destroy_sock(struct sock *sk) { + struct udp_sock *up = udp_sk(sk); bool slow = lock_sock_fast(sk); udp_flush_pending_frames(sk); unlock_sock_fast(sk, slow); + if (static_key_false(&udp_encap_needed) && up->encap_type) { + void (*encap_destroy)(struct sock *sk); + encap_destroy = ACCESS_ONCE(up->encap_destroy); + if (encap_destroy) + encap_destroy(sk); + } } /* diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 3ed57ec..da6019b 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1286,10 +1286,18 @@ do_confirm: void udpv6_destroy_sock(struct sock *sk) { + struct udp_sock *up = udp_sk(sk); lock_sock(sk); udp_v6_flush_pending_frames(sk); release_sock(sk); + if (static_key_false(&udpv6_encap_needed) && up->encap_type) { + void (*encap_destroy)(struct sock *sk); + encap_destroy = ACCESS_ONCE(up->encap_destroy); + if (encap_destroy) + encap_destroy(sk); + } + inet6_destroy_sock(sk); } -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 02/12] l2tp: add udp encap socket destroy handler 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin 2013-03-19 16:11 ` [PATCH 01/12] udp: add encap_destroy callback Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 03/12] l2tp: export l2tp_tunnel_closeall Tom Parkin ` (10 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman L2TP sessions hold a reference to the tunnel socket to prevent it going away while sessions are still active. However, since tunnel destruction is handled by the sock sk_destruct callback there is a catch-22: a tunnel with sessions cannot be deleted since each session holds a reference to the tunnel socket. If userspace closes a managed tunnel socket, or dies, the tunnel will persist and it will be neccessary to individually delete the sessions using netlink commands. This is ugly. To prevent this occuring, this patch leverages the udp encapsulation socket destroy callback to gain early notification when the tunnel socket is closed. This allows us to safely close the sessions running in the tunnel, dropping the tunnel socket references in the process. The tunnel socket is then destroyed as normal, and the tunnel resources deallocated in sk_destruct. While we're at it, ensure that l2tp_tunnel_closeall correctly drops session references to allow the sessions to be deleted rather than leaking. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index d36875f..ee726a7 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1282,6 +1282,7 @@ static void l2tp_tunnel_destruct(struct sock *sk) /* No longer an encapsulation socket. See net/ipv4/udp.c */ (udp_sk(sk))->encap_type = 0; (udp_sk(sk))->encap_rcv = NULL; + (udp_sk(sk))->encap_destroy = NULL; break; case L2TP_ENCAPTYPE_IP: break; @@ -1360,6 +1361,8 @@ again: if (session->deref != NULL) (*session->deref)(session); + l2tp_session_dec_refcount(session); + write_lock_bh(&tunnel->hlist_lock); /* Now restart from the beginning of this hash @@ -1373,6 +1376,16 @@ again: write_unlock_bh(&tunnel->hlist_lock); } +/* Tunnel socket destroy hook for UDP encapsulation */ +static void l2tp_udp_encap_destroy(struct sock *sk) +{ + struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); + if (tunnel) { + l2tp_tunnel_closeall(tunnel); + sock_put(sk); + } +} + /* Really kill the tunnel. * Come here only when all sessions have been cleared from the tunnel. */ @@ -1668,6 +1681,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; + udp_sk(sk)->encap_destroy = l2tp_udp_encap_destroy; #if IS_ENABLED(CONFIG_IPV6) if (sk->sk_family == PF_INET6) udpv6_encap_enable(); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 03/12] l2tp: export l2tp_tunnel_closeall 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin 2013-03-19 16:11 ` [PATCH 01/12] udp: add encap_destroy callback Tom Parkin 2013-03-19 16:11 ` [PATCH 02/12] l2tp: add udp encap socket destroy handler Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 04/12] l2tp: close sessions in ip socket destroy callback Tom Parkin ` (9 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman l2tp_core internally uses l2tp_tunnel_closeall to close all sessions in a tunnel when a UDP-encapsulation socket is destroyed. We need to do something similar for IP-encapsulation sockets. Export l2tp_tunnel_closeall as a GPL symbol to enable l2tp_ip and l2tp_ip6 to call it from their .destroy handlers. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 4 ++-- net/l2tp/l2tp_core.h | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index ee726a7..287e327 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -114,7 +114,6 @@ struct l2tp_net { static void l2tp_session_set_header_len(struct l2tp_session *session, int version); static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); -static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); static inline struct l2tp_net *l2tp_pernet(struct net *net) { @@ -1312,7 +1311,7 @@ end: /* When the tunnel is closed, all the attached sessions need to go too. */ -static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) +void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) { int hash; struct hlist_node *walk; @@ -1375,6 +1374,7 @@ again: } write_unlock_bh(&tunnel->hlist_lock); } +EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall); /* Tunnel socket destroy hook for UDP encapsulation */ static void l2tp_udp_encap_destroy(struct sock *sk) diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index 8eb8f1d..b0861f6 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -240,6 +240,7 @@ extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id); extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth); extern int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp); +extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); extern struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg); extern int l2tp_session_delete(struct l2tp_session *session); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 04/12] l2tp: close sessions in ip socket destroy callback 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (2 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 03/12] l2tp: export l2tp_tunnel_closeall Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 05/12] l2tp: close sessions before initiating tunnel delete Tom Parkin ` (8 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman l2tp_core hooks UDP's .destroy handler to gain advance warning of a tunnel socket being closed from userspace. We need to do the same thing for IP-encapsulation sockets. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_ip.c | 6 ++++++ net/l2tp/l2tp_ip6.c | 7 +++++++ 2 files changed, 13 insertions(+) diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 7f41b70..571db8d 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -228,10 +228,16 @@ static void l2tp_ip_close(struct sock *sk, long timeout) static void l2tp_ip_destroy_sock(struct sock *sk) { struct sk_buff *skb; + struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) kfree_skb(skb); + if (tunnel) { + l2tp_tunnel_closeall(tunnel); + sock_put(sk); + } + sk_refcnt_debug_dec(sk); } diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index 41f2f81..c74f5a9 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -241,10 +241,17 @@ static void l2tp_ip6_close(struct sock *sk, long timeout) static void l2tp_ip6_destroy_sock(struct sock *sk) { + struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); + lock_sock(sk); ip6_flush_pending_frames(sk); release_sock(sk); + if (tunnel) { + l2tp_tunnel_closeall(tunnel); + sock_put(sk); + } + inet6_destroy_sock(sk); } -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 05/12] l2tp: close sessions before initiating tunnel delete 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (3 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 04/12] l2tp: close sessions in ip socket destroy callback Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 06/12] l2tp: take a reference for kernel sockets in l2tp_tunnel_sock_lookup Tom Parkin ` (7 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman When a user deletes a tunnel using netlink, all the sessions in the tunnel should also be deleted. Since running sessions will pin the tunnel socket with the references they hold, have the l2tp_tunnel_delete close all sessions in a tunnel before finally closing the tunnel socket. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 287e327..0dd50c0 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1737,6 +1737,7 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_create); */ int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) { + l2tp_tunnel_closeall(tunnel); return (false == queue_work(l2tp_wq, &tunnel->del_work)); } EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 06/12] l2tp: take a reference for kernel sockets in l2tp_tunnel_sock_lookup 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (4 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 05/12] l2tp: close sessions before initiating tunnel delete Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 07/12] l2tp: don't BUG_ON sk_socket being NULL Tom Parkin ` (6 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman When looking up the tunnel socket in struct l2tp_tunnel, hold a reference whether the socket was created by the kernel or by userspace. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 0dd50c0..45373fe 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -191,6 +191,7 @@ struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel) } else { /* Socket is owned by kernelspace */ sk = tunnel->sock; + sock_hold(sk); } out: @@ -209,6 +210,7 @@ void l2tp_tunnel_sock_put(struct sock *sk) } sock_put(sk); } + sock_put(sk); } EXPORT_SYMBOL_GPL(l2tp_tunnel_sock_put); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 07/12] l2tp: don't BUG_ON sk_socket being NULL 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (5 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 06/12] l2tp: take a reference for kernel sockets in l2tp_tunnel_sock_lookup Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 08/12] l2tp: add session reorder queue purge function to core Tom Parkin ` (5 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman It is valid for an existing struct sock object to have a NULL sk_socket pointer, so don't BUG_ON in l2tp_tunnel_del_work if that should occur. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 45373fe..e841ef2 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1412,19 +1412,21 @@ static void l2tp_tunnel_del_work(struct work_struct *work) return; sock = sk->sk_socket; - BUG_ON(!sock); - /* If the tunnel socket was created directly by the kernel, use the - * sk_* API to release the socket now. Otherwise go through the - * inet_* layer to shut the socket down, and let userspace close it. + /* If the tunnel socket was created by userspace, then go through the + * inet layer to shut the socket down, and let userspace close it. + * Otherwise, if we created the socket directly within the kernel, use + * the sk API to release it here. * In either case the tunnel resources are freed in the socket * destructor when the tunnel socket goes away. */ - if (sock->file == NULL) { - kernel_sock_shutdown(sock, SHUT_RDWR); - sk_release_kernel(sk); + if (tunnel->fd >= 0) { + if (sock) + inet_shutdown(sock, 2); } else { - inet_shutdown(sock, 2); + if (sock) + kernel_sock_shutdown(sock, SHUT_RDWR); + sk_release_kernel(sk); } l2tp_tunnel_sock_put(sk); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 08/12] l2tp: add session reorder queue purge function to core 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (6 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 07/12] l2tp: don't BUG_ON sk_socket being NULL Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 09/12] l2tp: purge session reorder queue on delete Tom Parkin ` (4 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman If an l2tp session is deleted, it is necessary to delete skbs in-flight on the session's reorder queue before taking it down. Rather than having each pseudowire implementation reaching into the l2tp_session struct to handle this itself, provide a function in l2tp_core to purge the session queue. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 17 +++++++++++++++++ net/l2tp/l2tp_core.h | 1 + 2 files changed, 18 insertions(+) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index e841ef2..69c316d 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -829,6 +829,23 @@ discard: } EXPORT_SYMBOL(l2tp_recv_common); +/* Drop skbs from the session's reorder_q + */ +int l2tp_session_queue_purge(struct l2tp_session *session) +{ + struct sk_buff *skb = NULL; + BUG_ON(!session); + BUG_ON(session->magic != L2TP_SESSION_MAGIC); + while ((skb = skb_dequeue(&session->reorder_q))) { + atomic_long_inc(&session->stats.rx_errors); + kfree_skb(skb); + if (session->deref) + (*session->deref)(session); + } + return 0; +} +EXPORT_SYMBOL_GPL(l2tp_session_queue_purge); + /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame * here. The skb is not on a list when we get here. * Returns 0 if the packet was a data packet and was successfully passed on. diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index b0861f6..d40713d 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -246,6 +246,7 @@ extern struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunne extern int l2tp_session_delete(struct l2tp_session *session); extern void l2tp_session_free(struct l2tp_session *session); extern void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length, int (*payload_hook)(struct sk_buff *skb)); +extern int l2tp_session_queue_purge(struct l2tp_session *session); extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 09/12] l2tp: purge session reorder queue on delete 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (7 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 08/12] l2tp: add session reorder queue purge function to core Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 10/12] l2tp: push all ppp pseudowire shutdown through .release handler Tom Parkin ` (3 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman Add calls to l2tp_session_queue_purge as a part of l2tp_tunnel_closeall and l2tp_session_delete. Pseudowire implementations which are deleted only via. l2tp_core l2tp_session_delete calls can dispense with their own code for flushing the reorder queue. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 69c316d..c00f31b 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1373,6 +1373,8 @@ again: synchronize_rcu(); } + l2tp_session_queue_purge(session); + if (session->session_close != NULL) (*session->session_close)(session); @@ -1813,6 +1815,8 @@ EXPORT_SYMBOL_GPL(l2tp_session_free); */ int l2tp_session_delete(struct l2tp_session *session) { + l2tp_session_queue_purge(session); + if (session->session_close != NULL) (*session->session_close)(session); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 10/12] l2tp: push all ppp pseudowire shutdown through .release handler 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (8 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 09/12] l2tp: purge session reorder queue on delete Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 11/12] l2tp: avoid deadlock in l2tp stats update Tom Parkin ` (2 subsequent siblings) 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman If userspace deletes a ppp pseudowire using the netlink API, either by directly deleting the session or by deleting the tunnel that contains the session, we need to tear down the corresponding pppox channel. Rather than trying to manage two pppox unbind codepaths, switch the netlink and l2tp_core session_close handlers to close via. the l2tp_ppp socket .release handler. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_ppp.c | 53 ++++++++++----------------------------------------- 1 file changed, 10 insertions(+), 43 deletions(-) diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 6a53371..7e3e16a 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -97,6 +97,7 @@ #include <net/ip.h> #include <net/udp.h> #include <net/xfrm.h> +#include <net/inet_common.h> #include <asm/byteorder.h> #include <linux/atomic.h> @@ -447,34 +448,16 @@ static void pppol2tp_session_close(struct l2tp_session *session) { struct pppol2tp_session *ps = l2tp_session_priv(session); struct sock *sk = ps->sock; - struct sk_buff *skb; + struct socket *sock = sk->sk_socket; BUG_ON(session->magic != L2TP_SESSION_MAGIC); - if (session->session_id == 0) - goto out; - - if (sk != NULL) { - lock_sock(sk); - - if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) { - pppox_unbind_sock(sk); - sk->sk_state = PPPOX_DEAD; - sk->sk_state_change(sk); - } - - /* Purge any queued data */ - skb_queue_purge(&sk->sk_receive_queue); - skb_queue_purge(&sk->sk_write_queue); - while ((skb = skb_dequeue(&session->reorder_q))) { - kfree_skb(skb); - sock_put(sk); - } - release_sock(sk); + if (sock) { + inet_shutdown(sock, 2); + /* Don't let the session go away before our socket does */ + l2tp_session_inc_refcount(session); } - -out: return; } @@ -525,16 +508,12 @@ static int pppol2tp_release(struct socket *sock) session = pppol2tp_sock_to_session(sk); /* Purge any queued data */ - skb_queue_purge(&sk->sk_receive_queue); - skb_queue_purge(&sk->sk_write_queue); if (session != NULL) { - struct sk_buff *skb; - while ((skb = skb_dequeue(&session->reorder_q))) { - kfree_skb(skb); - sock_put(sk); - } + l2tp_session_queue_purge(session); sock_put(sk); } + skb_queue_purge(&sk->sk_receive_queue); + skb_queue_purge(&sk->sk_write_queue); release_sock(sk); @@ -880,18 +859,6 @@ out: return error; } -/* Called when deleting sessions via the netlink interface. - */ -static int pppol2tp_session_delete(struct l2tp_session *session) -{ - struct pppol2tp_session *ps = l2tp_session_priv(session); - - if (ps->sock == NULL) - l2tp_session_dec_refcount(session); - - return 0; -} - #endif /* CONFIG_L2TP_V3 */ /* getname() support. @@ -1839,7 +1806,7 @@ static const struct pppox_proto pppol2tp_proto = { static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = { .session_create = pppol2tp_session_create, - .session_delete = pppol2tp_session_delete, + .session_delete = l2tp_session_delete, }; #endif /* CONFIG_L2TP_V3 */ -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 11/12] l2tp: avoid deadlock in l2tp stats update 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (9 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 10/12] l2tp: push all ppp pseudowire shutdown through .release handler Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-19 16:11 ` [PATCH 12/12] l2tp: unhash l2tp sessions on delete, not on free Tom Parkin 2013-03-20 16:14 ` [PATCH 00/12] l2tp bugfix patchset David Miller 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman l2tp's u64_stats writers were incorrectly synchronised, making it possible to deadlock a 64bit machine running a 32bit kernel simply by sending the l2tp code netlink commands while passing data through l2tp sessions. Previous discussion on netdev determined that alternative solutions such as spinlock writer synchronisation or per-cpu data would bring unjustified overhead, given that most users interested in high volume traffic will likely be running 64bit kernels on 64bit hardware. As such, this patch replaces l2tp's use of u64_stats with atomic_long_t, thereby avoiding the deadlock. Ref: http://marc.info/?l=linux-netdev&m=134029167910731&w=2 http://marc.info/?l=linux-netdev&m=134079868111131&w=2 Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 75 ++++++++++++----------------------------------- net/l2tp/l2tp_core.h | 19 ++++++------ net/l2tp/l2tp_debugfs.c | 28 +++++++++--------- net/l2tp/l2tp_netlink.c | 72 ++++++++++++++++++--------------------------- net/l2tp/l2tp_ppp.c | 46 ++++++++++++++--------------- 5 files changed, 93 insertions(+), 147 deletions(-) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index c00f31b..97d30ac 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -374,10 +374,8 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk struct sk_buff *skbp; struct sk_buff *tmp; u32 ns = L2TP_SKB_CB(skb)->ns; - struct l2tp_stats *sstats; spin_lock_bh(&session->reorder_q.lock); - sstats = &session->stats; skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { if (L2TP_SKB_CB(skbp)->ns > ns) { __skb_queue_before(&session->reorder_q, skbp, skb); @@ -385,9 +383,7 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", session->name, ns, L2TP_SKB_CB(skbp)->ns, skb_queue_len(&session->reorder_q)); - u64_stats_update_begin(&sstats->syncp); - sstats->rx_oos_packets++; - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&session->stats.rx_oos_packets); goto out; } } @@ -404,23 +400,16 @@ static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff * { struct l2tp_tunnel *tunnel = session->tunnel; int length = L2TP_SKB_CB(skb)->length; - struct l2tp_stats *tstats, *sstats; /* We're about to requeue the skb, so return resources * to its current owner (a socket receive buffer). */ skb_orphan(skb); - tstats = &tunnel->stats; - u64_stats_update_begin(&tstats->syncp); - sstats = &session->stats; - u64_stats_update_begin(&sstats->syncp); - tstats->rx_packets++; - tstats->rx_bytes += length; - sstats->rx_packets++; - sstats->rx_bytes += length; - u64_stats_update_end(&tstats->syncp); - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&tunnel->stats.rx_packets); + atomic_long_add(length, &tunnel->stats.rx_bytes); + atomic_long_inc(&session->stats.rx_packets); + atomic_long_add(length, &session->stats.rx_bytes); if (L2TP_SKB_CB(skb)->has_seq) { /* Bump our Nr */ @@ -451,7 +440,6 @@ static void l2tp_recv_dequeue(struct l2tp_session *session) { struct sk_buff *skb; struct sk_buff *tmp; - struct l2tp_stats *sstats; /* If the pkt at the head of the queue has the nr that we * expect to send up next, dequeue it and any other @@ -459,13 +447,10 @@ static void l2tp_recv_dequeue(struct l2tp_session *session) */ start: spin_lock_bh(&session->reorder_q.lock); - sstats = &session->stats; skb_queue_walk_safe(&session->reorder_q, skb, tmp) { if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { - u64_stats_update_begin(&sstats->syncp); - sstats->rx_seq_discards++; - sstats->rx_errors++; - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&session->stats.rx_seq_discards); + atomic_long_inc(&session->stats.rx_errors); l2tp_dbg(session, L2TP_MSG_SEQ, "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n", session->name, L2TP_SKB_CB(skb)->ns, @@ -624,7 +609,6 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, struct l2tp_tunnel *tunnel = session->tunnel; int offset; u32 ns, nr; - struct l2tp_stats *sstats = &session->stats; /* The ref count is increased since we now hold a pointer to * the session. Take care to decrement the refcnt when exiting @@ -641,9 +625,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, "%s: cookie mismatch (%u/%u). Discarding.\n", tunnel->name, tunnel->tunnel_id, session->session_id); - u64_stats_update_begin(&sstats->syncp); - sstats->rx_cookie_discards++; - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&session->stats.rx_cookie_discards); goto discard; } ptr += session->peer_cookie_len; @@ -712,9 +694,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, l2tp_warn(session, L2TP_MSG_SEQ, "%s: recv data has no seq numbers when required. Discarding.\n", session->name); - u64_stats_update_begin(&sstats->syncp); - sstats->rx_seq_discards++; - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&session->stats.rx_seq_discards); goto discard; } @@ -733,9 +713,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, l2tp_warn(session, L2TP_MSG_SEQ, "%s: recv data has no seq numbers when required. Discarding.\n", session->name); - u64_stats_update_begin(&sstats->syncp); - sstats->rx_seq_discards++; - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&session->stats.rx_seq_discards); goto discard; } } @@ -789,9 +767,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, * packets */ if (L2TP_SKB_CB(skb)->ns != session->nr) { - u64_stats_update_begin(&sstats->syncp); - sstats->rx_seq_discards++; - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&session->stats.rx_seq_discards); l2tp_dbg(session, L2TP_MSG_SEQ, "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n", session->name, L2TP_SKB_CB(skb)->ns, @@ -817,9 +793,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, return; discard: - u64_stats_update_begin(&sstats->syncp); - sstats->rx_errors++; - u64_stats_update_end(&sstats->syncp); + atomic_long_inc(&session->stats.rx_errors); kfree_skb(skb); if (session->deref) @@ -861,7 +835,6 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, u32 tunnel_id, session_id; u16 version; int length; - struct l2tp_stats *tstats; if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb)) goto discard_bad_csum; @@ -950,10 +923,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, discard_bad_csum: LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); - tstats = &tunnel->stats; - u64_stats_update_begin(&tstats->syncp); - tstats->rx_errors++; - u64_stats_update_end(&tstats->syncp); + atomic_long_inc(&tunnel->stats.rx_errors); kfree_skb(skb); return 0; @@ -1080,7 +1050,6 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, struct l2tp_tunnel *tunnel = session->tunnel; unsigned int len = skb->len; int error; - struct l2tp_stats *tstats, *sstats; /* Debug */ if (session->send_seq) @@ -1109,21 +1078,15 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, error = ip_queue_xmit(skb, fl); /* Update stats */ - tstats = &tunnel->stats; - u64_stats_update_begin(&tstats->syncp); - sstats = &session->stats; - u64_stats_update_begin(&sstats->syncp); if (error >= 0) { - tstats->tx_packets++; - tstats->tx_bytes += len; - sstats->tx_packets++; - sstats->tx_bytes += len; + atomic_long_inc(&tunnel->stats.tx_packets); + atomic_long_add(len, &tunnel->stats.tx_bytes); + atomic_long_inc(&session->stats.tx_packets); + atomic_long_add(len, &session->stats.tx_bytes); } else { - tstats->tx_errors++; - sstats->tx_errors++; + atomic_long_inc(&tunnel->stats.tx_errors); + atomic_long_inc(&session->stats.tx_errors); } - u64_stats_update_end(&tstats->syncp); - u64_stats_update_end(&sstats->syncp); return 0; } diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index d40713d..519b013 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -36,16 +36,15 @@ enum { struct sk_buff; struct l2tp_stats { - u64 tx_packets; - u64 tx_bytes; - u64 tx_errors; - u64 rx_packets; - u64 rx_bytes; - u64 rx_seq_discards; - u64 rx_oos_packets; - u64 rx_errors; - u64 rx_cookie_discards; - struct u64_stats_sync syncp; + atomic_long_t tx_packets; + atomic_long_t tx_bytes; + atomic_long_t tx_errors; + atomic_long_t rx_packets; + atomic_long_t rx_bytes; + atomic_long_t rx_seq_discards; + atomic_long_t rx_oos_packets; + atomic_long_t rx_errors; + atomic_long_t rx_cookie_discards; }; struct l2tp_tunnel; diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c index c3813bc..072d720 100644 --- a/net/l2tp/l2tp_debugfs.c +++ b/net/l2tp/l2tp_debugfs.c @@ -146,14 +146,14 @@ static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v) tunnel->sock ? atomic_read(&tunnel->sock->sk_refcnt) : 0, atomic_read(&tunnel->ref_count)); - seq_printf(m, " %08x rx %llu/%llu/%llu rx %llu/%llu/%llu\n", + seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n", tunnel->debug, - (unsigned long long)tunnel->stats.tx_packets, - (unsigned long long)tunnel->stats.tx_bytes, - (unsigned long long)tunnel->stats.tx_errors, - (unsigned long long)tunnel->stats.rx_packets, - (unsigned long long)tunnel->stats.rx_bytes, - (unsigned long long)tunnel->stats.rx_errors); + atomic_long_read(&tunnel->stats.tx_packets), + atomic_long_read(&tunnel->stats.tx_bytes), + atomic_long_read(&tunnel->stats.tx_errors), + atomic_long_read(&tunnel->stats.rx_packets), + atomic_long_read(&tunnel->stats.rx_bytes), + atomic_long_read(&tunnel->stats.rx_errors)); if (tunnel->show != NULL) tunnel->show(m, tunnel); @@ -203,14 +203,14 @@ static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v) seq_printf(m, "\n"); } - seq_printf(m, " %hu/%hu tx %llu/%llu/%llu rx %llu/%llu/%llu\n", + seq_printf(m, " %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n", session->nr, session->ns, - (unsigned long long)session->stats.tx_packets, - (unsigned long long)session->stats.tx_bytes, - (unsigned long long)session->stats.tx_errors, - (unsigned long long)session->stats.rx_packets, - (unsigned long long)session->stats.rx_bytes, - (unsigned long long)session->stats.rx_errors); + atomic_long_read(&session->stats.tx_packets), + atomic_long_read(&session->stats.tx_bytes), + atomic_long_read(&session->stats.tx_errors), + atomic_long_read(&session->stats.rx_packets), + atomic_long_read(&session->stats.rx_bytes), + atomic_long_read(&session->stats.rx_errors)); if (session->show != NULL) session->show(m, session); diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c index c1bab22..0825ff2 100644 --- a/net/l2tp/l2tp_netlink.c +++ b/net/l2tp/l2tp_netlink.c @@ -246,8 +246,6 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int fla #if IS_ENABLED(CONFIG_IPV6) struct ipv6_pinfo *np = NULL; #endif - struct l2tp_stats stats; - unsigned int start; hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, L2TP_CMD_TUNNEL_GET); @@ -265,28 +263,22 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int fla if (nest == NULL) goto nla_put_failure; - do { - start = u64_stats_fetch_begin(&tunnel->stats.syncp); - stats.tx_packets = tunnel->stats.tx_packets; - stats.tx_bytes = tunnel->stats.tx_bytes; - stats.tx_errors = tunnel->stats.tx_errors; - stats.rx_packets = tunnel->stats.rx_packets; - stats.rx_bytes = tunnel->stats.rx_bytes; - stats.rx_errors = tunnel->stats.rx_errors; - stats.rx_seq_discards = tunnel->stats.rx_seq_discards; - stats.rx_oos_packets = tunnel->stats.rx_oos_packets; - } while (u64_stats_fetch_retry(&tunnel->stats.syncp, start)); - - if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, stats.tx_packets) || - nla_put_u64(skb, L2TP_ATTR_TX_BYTES, stats.tx_bytes) || - nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, stats.tx_errors) || - nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, stats.rx_packets) || - nla_put_u64(skb, L2TP_ATTR_RX_BYTES, stats.rx_bytes) || + if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, + atomic_long_read(&tunnel->stats.tx_packets)) || + nla_put_u64(skb, L2TP_ATTR_TX_BYTES, + atomic_long_read(&tunnel->stats.tx_bytes)) || + nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, + atomic_long_read(&tunnel->stats.tx_errors)) || + nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, + atomic_long_read(&tunnel->stats.rx_packets)) || + nla_put_u64(skb, L2TP_ATTR_RX_BYTES, + atomic_long_read(&tunnel->stats.rx_bytes)) || nla_put_u64(skb, L2TP_ATTR_RX_SEQ_DISCARDS, - stats.rx_seq_discards) || + atomic_long_read(&tunnel->stats.rx_seq_discards)) || nla_put_u64(skb, L2TP_ATTR_RX_OOS_PACKETS, - stats.rx_oos_packets) || - nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, stats.rx_errors)) + atomic_long_read(&tunnel->stats.rx_oos_packets)) || + nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, + atomic_long_read(&tunnel->stats.rx_errors))) goto nla_put_failure; nla_nest_end(skb, nest); @@ -612,8 +604,6 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int fl struct nlattr *nest; struct l2tp_tunnel *tunnel = session->tunnel; struct sock *sk = NULL; - struct l2tp_stats stats; - unsigned int start; sk = tunnel->sock; @@ -656,28 +646,22 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int fl if (nest == NULL) goto nla_put_failure; - do { - start = u64_stats_fetch_begin(&session->stats.syncp); - stats.tx_packets = session->stats.tx_packets; - stats.tx_bytes = session->stats.tx_bytes; - stats.tx_errors = session->stats.tx_errors; - stats.rx_packets = session->stats.rx_packets; - stats.rx_bytes = session->stats.rx_bytes; - stats.rx_errors = session->stats.rx_errors; - stats.rx_seq_discards = session->stats.rx_seq_discards; - stats.rx_oos_packets = session->stats.rx_oos_packets; - } while (u64_stats_fetch_retry(&session->stats.syncp, start)); - - if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, stats.tx_packets) || - nla_put_u64(skb, L2TP_ATTR_TX_BYTES, stats.tx_bytes) || - nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, stats.tx_errors) || - nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, stats.rx_packets) || - nla_put_u64(skb, L2TP_ATTR_RX_BYTES, stats.rx_bytes) || + if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, + atomic_long_read(&session->stats.tx_packets)) || + nla_put_u64(skb, L2TP_ATTR_TX_BYTES, + atomic_long_read(&session->stats.tx_bytes)) || + nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, + atomic_long_read(&session->stats.tx_errors)) || + nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, + atomic_long_read(&session->stats.rx_packets)) || + nla_put_u64(skb, L2TP_ATTR_RX_BYTES, + atomic_long_read(&session->stats.rx_bytes)) || nla_put_u64(skb, L2TP_ATTR_RX_SEQ_DISCARDS, - stats.rx_seq_discards) || + atomic_long_read(&session->stats.rx_seq_discards)) || nla_put_u64(skb, L2TP_ATTR_RX_OOS_PACKETS, - stats.rx_oos_packets) || - nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, stats.rx_errors)) + atomic_long_read(&session->stats.rx_oos_packets)) || + nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, + atomic_long_read(&session->stats.rx_errors))) goto nla_put_failure; nla_nest_end(skb, nest); diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 7e3e16a..9d0eb8c 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -260,7 +260,7 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int session->name); /* Not bound. Nothing we can do, so discard. */ - session->stats.rx_errors++; + atomic_long_inc(&session->stats.rx_errors); kfree_skb(skb); } @@ -992,14 +992,14 @@ end: static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest, struct l2tp_stats *stats) { - dest->tx_packets = stats->tx_packets; - dest->tx_bytes = stats->tx_bytes; - dest->tx_errors = stats->tx_errors; - dest->rx_packets = stats->rx_packets; - dest->rx_bytes = stats->rx_bytes; - dest->rx_seq_discards = stats->rx_seq_discards; - dest->rx_oos_packets = stats->rx_oos_packets; - dest->rx_errors = stats->rx_errors; + dest->tx_packets = atomic_long_read(&stats->tx_packets); + dest->tx_bytes = atomic_long_read(&stats->tx_bytes); + dest->tx_errors = atomic_long_read(&stats->tx_errors); + dest->rx_packets = atomic_long_read(&stats->rx_packets); + dest->rx_bytes = atomic_long_read(&stats->rx_bytes); + dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards); + dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets); + dest->rx_errors = atomic_long_read(&stats->rx_errors); } /* Session ioctl helper. @@ -1633,14 +1633,14 @@ static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v) tunnel->name, (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N', atomic_read(&tunnel->ref_count) - 1); - seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n", + seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n", tunnel->debug, - (unsigned long long)tunnel->stats.tx_packets, - (unsigned long long)tunnel->stats.tx_bytes, - (unsigned long long)tunnel->stats.tx_errors, - (unsigned long long)tunnel->stats.rx_packets, - (unsigned long long)tunnel->stats.rx_bytes, - (unsigned long long)tunnel->stats.rx_errors); + atomic_long_read(&tunnel->stats.tx_packets), + atomic_long_read(&tunnel->stats.tx_bytes), + atomic_long_read(&tunnel->stats.tx_errors), + atomic_long_read(&tunnel->stats.rx_packets), + atomic_long_read(&tunnel->stats.rx_bytes), + atomic_long_read(&tunnel->stats.rx_errors)); } static void pppol2tp_seq_session_show(struct seq_file *m, void *v) @@ -1675,14 +1675,14 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v) session->lns_mode ? "LNS" : "LAC", session->debug, jiffies_to_msecs(session->reorder_timeout)); - seq_printf(m, " %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n", + seq_printf(m, " %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n", session->nr, session->ns, - (unsigned long long)session->stats.tx_packets, - (unsigned long long)session->stats.tx_bytes, - (unsigned long long)session->stats.tx_errors, - (unsigned long long)session->stats.rx_packets, - (unsigned long long)session->stats.rx_bytes, - (unsigned long long)session->stats.rx_errors); + atomic_long_read(&session->stats.tx_packets), + atomic_long_read(&session->stats.tx_bytes), + atomic_long_read(&session->stats.tx_errors), + atomic_long_read(&session->stats.rx_packets), + atomic_long_read(&session->stats.rx_bytes), + atomic_long_read(&session->stats.rx_errors)); if (po) seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan)); -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 12/12] l2tp: unhash l2tp sessions on delete, not on free 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (10 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 11/12] l2tp: avoid deadlock in l2tp stats update Tom Parkin @ 2013-03-19 16:11 ` Tom Parkin 2013-03-20 16:14 ` [PATCH 00/12] l2tp bugfix patchset David Miller 12 siblings, 0 replies; 14+ messages in thread From: Tom Parkin @ 2013-03-19 16:11 UTC (permalink / raw) To: netdev; +Cc: Tom Parkin, James Chapman If we postpone unhashing of l2tp sessions until the structure is freed, we risk: 1. further packets arriving and getting queued while the pseudowire is being closed down 2. the recv path hitting "scheduling while atomic" errors in the case that recv drops the last reference to a session and calls l2tp_session_free while in atomic context As such, l2tp sessions should be unhashed from l2tp_core data structures early in the teardown process prior to calling pseudowire close. For pseudowires like l2tp_ppp which have multiple shutdown codepaths, provide an unhash hook. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 75 +++++++++++++++++++++++--------------------------- net/l2tp/l2tp_core.h | 1 + net/l2tp/l2tp_ppp.c | 12 ++------ 3 files changed, 38 insertions(+), 50 deletions(-) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 97d30ac..8aecf5d 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1316,26 +1316,12 @@ again: hlist_del_init(&session->hlist); - /* Since we should hold the sock lock while - * doing any unbinding, we need to release the - * lock we're holding before taking that lock. - * Hold a reference to the sock so it doesn't - * disappear as we're jumping between locks. - */ if (session->ref != NULL) (*session->ref)(session); write_unlock_bh(&tunnel->hlist_lock); - if (tunnel->version != L2TP_HDR_VER_2) { - struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); - - spin_lock_bh(&pn->l2tp_session_hlist_lock); - hlist_del_init_rcu(&session->global_hlist); - spin_unlock_bh(&pn->l2tp_session_hlist_lock); - synchronize_rcu(); - } - + __l2tp_session_unhash(session); l2tp_session_queue_purge(session); if (session->session_close != NULL) @@ -1732,64 +1718,71 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); */ void l2tp_session_free(struct l2tp_session *session) { - struct l2tp_tunnel *tunnel; + struct l2tp_tunnel *tunnel = session->tunnel; BUG_ON(atomic_read(&session->ref_count) != 0); - tunnel = session->tunnel; - if (tunnel != NULL) { + if (tunnel) { BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); + if (session->session_id != 0) + atomic_dec(&l2tp_session_count); + sock_put(tunnel->sock); + session->tunnel = NULL; + l2tp_tunnel_dec_refcount(tunnel); + } + + kfree(session); + + return; +} +EXPORT_SYMBOL_GPL(l2tp_session_free); + +/* Remove an l2tp session from l2tp_core's hash lists. + * Provides a tidyup interface for pseudowire code which can't just route all + * shutdown via. l2tp_session_delete and a pseudowire-specific session_close + * callback. + */ +void __l2tp_session_unhash(struct l2tp_session *session) +{ + struct l2tp_tunnel *tunnel = session->tunnel; - /* Delete the session from the hash */ + /* Remove the session from core hashes */ + if (tunnel) { + /* Remove from the per-tunnel hash */ write_lock_bh(&tunnel->hlist_lock); hlist_del_init(&session->hlist); write_unlock_bh(&tunnel->hlist_lock); - /* Unlink from the global hash if not L2TPv2 */ + /* For L2TPv3 we have a per-net hash: remove from there, too */ if (tunnel->version != L2TP_HDR_VER_2) { struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); - spin_lock_bh(&pn->l2tp_session_hlist_lock); hlist_del_init_rcu(&session->global_hlist); spin_unlock_bh(&pn->l2tp_session_hlist_lock); synchronize_rcu(); } - - if (session->session_id != 0) - atomic_dec(&l2tp_session_count); - - sock_put(tunnel->sock); - - /* This will delete the tunnel context if this - * is the last session on the tunnel. - */ - session->tunnel = NULL; - l2tp_tunnel_dec_refcount(tunnel); } - - kfree(session); - - return; } -EXPORT_SYMBOL_GPL(l2tp_session_free); +EXPORT_SYMBOL_GPL(__l2tp_session_unhash); /* This function is used by the netlink SESSION_DELETE command and by pseudowire modules. */ int l2tp_session_delete(struct l2tp_session *session) { + if (session->ref) + (*session->ref)(session); + __l2tp_session_unhash(session); l2tp_session_queue_purge(session); - if (session->session_close != NULL) (*session->session_close)(session); - + if (session->deref) + (*session->ref)(session); l2tp_session_dec_refcount(session); - return 0; } EXPORT_SYMBOL_GPL(l2tp_session_delete); - /* We come here whenever a session's send_seq, cookie_len or * l2specific_len parameters are set. */ diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index 519b013..485a490 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -242,6 +242,7 @@ extern int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_i extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); extern struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg); +extern void __l2tp_session_unhash(struct l2tp_session *session); extern int l2tp_session_delete(struct l2tp_session *session); extern void l2tp_session_free(struct l2tp_session *session); extern void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length, int (*payload_hook)(struct sk_buff *skb)); diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 9d0eb8c..637a341 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -466,19 +466,12 @@ static void pppol2tp_session_close(struct l2tp_session *session) */ static void pppol2tp_session_destruct(struct sock *sk) { - struct l2tp_session *session; - - if (sk->sk_user_data != NULL) { - session = sk->sk_user_data; - if (session == NULL) - goto out; - + struct l2tp_session *session = sk->sk_user_data; + if (session) { sk->sk_user_data = NULL; BUG_ON(session->magic != L2TP_SESSION_MAGIC); l2tp_session_dec_refcount(session); } - -out: return; } @@ -509,6 +502,7 @@ static int pppol2tp_release(struct socket *sock) /* Purge any queued data */ if (session != NULL) { + __l2tp_session_unhash(session); l2tp_session_queue_purge(session); sock_put(sk); } -- 1.7.9.5 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH 00/12] l2tp bugfix patchset 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin ` (11 preceding siblings ...) 2013-03-19 16:11 ` [PATCH 12/12] l2tp: unhash l2tp sessions on delete, not on free Tom Parkin @ 2013-03-20 16:14 ` David Miller 12 siblings, 0 replies; 14+ messages in thread From: David Miller @ 2013-03-20 16:14 UTC (permalink / raw) To: tparkin; +Cc: netdev From: Tom Parkin <tparkin@katalix.com> Date: Tue, 19 Mar 2013 16:11:11 +0000 > This l2tp bugfix patchset addresses a number of issues. > > The first five patches in the series prevent l2tp sessions pinning an l2tp > tunnel open. This occurs because the l2tp tunnel is torn down in the tunnel > socket destructor, but each session holds a tunnel socket reference which > prevents tunnels with sessions being deleted. The solution I've implemented > here involves adding a .destroy hook to udp code, as discussed previously on > netdev[1]. > > The subsequent seven patches address futher bugs exposed by fixing the problem > above, or exposed through stress testing the implementation above. Patch 11 > (avoid deadlock in l2tp stats update) isn't directly related to tunnel/session > lifetimes, but it does prevent deadlocks on i386 kernels running on 64 bit > hardware. > > This patchset has been tested on 32 and 64 bit preempt/non-preempt kernels, > using iproute2, openl2tp, and custom-made stress test code. > > [1] http://comments.gmane.org/gmane.linux.network/259169 All applied, thanks for fixing all of these bugs Tom. ^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2013-03-20 16:14 UTC | newest] Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2013-03-19 16:11 [PATCH 00/12] l2tp bugfix patchset Tom Parkin 2013-03-19 16:11 ` [PATCH 01/12] udp: add encap_destroy callback Tom Parkin 2013-03-19 16:11 ` [PATCH 02/12] l2tp: add udp encap socket destroy handler Tom Parkin 2013-03-19 16:11 ` [PATCH 03/12] l2tp: export l2tp_tunnel_closeall Tom Parkin 2013-03-19 16:11 ` [PATCH 04/12] l2tp: close sessions in ip socket destroy callback Tom Parkin 2013-03-19 16:11 ` [PATCH 05/12] l2tp: close sessions before initiating tunnel delete Tom Parkin 2013-03-19 16:11 ` [PATCH 06/12] l2tp: take a reference for kernel sockets in l2tp_tunnel_sock_lookup Tom Parkin 2013-03-19 16:11 ` [PATCH 07/12] l2tp: don't BUG_ON sk_socket being NULL Tom Parkin 2013-03-19 16:11 ` [PATCH 08/12] l2tp: add session reorder queue purge function to core Tom Parkin 2013-03-19 16:11 ` [PATCH 09/12] l2tp: purge session reorder queue on delete Tom Parkin 2013-03-19 16:11 ` [PATCH 10/12] l2tp: push all ppp pseudowire shutdown through .release handler Tom Parkin 2013-03-19 16:11 ` [PATCH 11/12] l2tp: avoid deadlock in l2tp stats update Tom Parkin 2013-03-19 16:11 ` [PATCH 12/12] l2tp: unhash l2tp sessions on delete, not on free Tom Parkin 2013-03-20 16:14 ` [PATCH 00/12] l2tp bugfix patchset David Miller
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