kernel.git/net/core/sock.c, branch linux-2.6.36.y

net: fix a lockdep splat

2010-09-25T05:26:10Z

We have for each socket : One spinlock (sk_slock.slock) One rwlock (sk_callback_lock) Possible scenarios are : (A) (this is used in net/sunrpc/xprtsock.c) read_lock(&sk->sk_callback_lock) (without blocking BH) spin_lock(&sk->sk_slock.slock); ... read_lock(&sk->sk_callback_lock); ... (B) write_lock_bh(&sk->sk_callback_lock) stuff write_unlock_bh(&sk->sk_callback_lock) (C) spin_lock_bh(&sk->sk_slock) ... write_lock_bh(&sk->sk_callback_lock) stuff write_unlock_bh(&sk->sk_callback_lock) spin_unlock_bh(&sk->sk_slock) This (C) case conflicts with (A) : CPU1 [A] CPU2 [C] read_lock(callback_lock) spin_lock_bh(slock) We have one problematic (C) use case in inet_csk_listen_stop() : local_bh_disable(); bh_lock_sock(child); // spin_lock_bh(&sk->sk_slock) WARN_ON(sock_owned_by_user(child)); ... sock_orphan(child); // write_lock_bh(&sk->sk_callback_lock) lockdep is not happy with this, as reported by Tetsuo Handa It seems only way to deal with this is to use read_lock_bh(callbacklock) everywhere. Thanks to Jarek for pointing a bug in my first attempt and suggesting this solution. Reported-by: Tetsuo Handa Tested-by: Tetsuo Handa Signed-off-by: Eric Dumazet CC: Jarek Poplawski Tested-by: Eric Dumazet Signed-off-by: David S. Miller

net: this_cpu_xxx conversions

2010-07-19T22:12:51Z

Use modern this_cpu_xxx() api, saving few bytes on x86 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: sock_free() optimizations

2010-07-13T03:21:46Z

Avoid two extra instructions in sock_free(), to reload skb->truesize and skb->sk Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: Export cred_to_ucred to modules.

2010-06-16T23:18:25Z

AF_UNIX references this, and can be built as a module, so... Signed-off-by: David S. Miller

af_unix: Allow SO_PEERCRED to work across namespaces.

2010-06-16T21:55:55Z

Use struct pid and struct cred to store the peer credentials on struct sock. This gives enough information to convert the peer credential information to a value relative to whatever namespace the socket is in at the time. This removes nasty surprises when using SO_PEERCRED on socket connetions where the processes on either side are in different pid and user namespaces. Signed-off-by: Eric W. Biederman Acked-by: Daniel Lezcano Acked-by: Pavel Emelyanov Signed-off-by: David S. Miller

sock: Introduce cred_to_ucred

2010-06-16T21:55:35Z

To keep the coming code clear and to allow both the sock code and the scm code to share the logic introduce a fuction to translate from struct cred to struct ucred. Signed-off-by: Eric W. Biederman Acked-by: Pavel Emelyanov Signed-off-by: David S. Miller

net-caif: Added missing lock validator constants

2010-06-07T08:01:22Z

CAIF is using "xxx-AF_MAX" strings for the lock validator. It should use its own strings. Signed-off-by: Alex Lorca Signed-off-by: David S. Miller

net: fix lock_sock_bh/unlock_sock_bh

2010-05-27T07:30:53Z

This new sock lock primitive was introduced to speedup some user context socket manipulation. But it is unsafe to protect two threads, one using regular lock_sock/release_sock, one using lock_sock_bh/unlock_sock_bh This patch changes lock_sock_bh to be careful against 'owned' state. If owned is found to be set, we must take the slow path. lock_sock_bh() now returns a boolean to say if the slow path was taken, and this boolean is used at unlock_sock_bh time to call the appropriate unlock function. After this change, BH are either disabled or enabled during the lock_sock_bh/unlock_sock_bh protected section. This might be misleading, so we rename these functions to lock_sock_fast()/unlock_sock_fast(). Reported-by: Anton Blanchard Signed-off-by: Eric Dumazet Tested-by: Anton Blanchard Signed-off-by: David S. Miller

tun: Update classid on packet injection

2010-05-24T07:14:10Z

This patch makes tun update its socket classid every time we inject a packet into the network stack. This is so that any updates made by the admin to the process writing packets to tun is effected. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller

cls_cgroup: Store classid in struct sock

2010-05-24T07:12:34Z

Up until now cls_cgroup has relied on fetching the classid out of the current executing thread. This runs into trouble when a packet processing is delayed in which case it may execute out of another thread's context. Furthermore, even when a packet is not delayed we may fail to classify it if soft IRQs have been disabled, because this scenario is indistinguishable from one where a packet unrelated to the current thread is processed by a real soft IRQ. In fact, the current semantics is inherently broken, as a single skb may be constructed out of the writes of two different tasks. A different manifestation of this problem is when the TCP stack transmits in response of an incoming ACK. This is currently unclassified. As we already have a concept of packet ownership for accounting purposes in the skb->sk pointer, this is a natural place to store the classid in a persistent manner. This patch adds the cls_cgroup classid in struct sock, filling up an existing hole on 64-bit :) The value is set at socket creation time. So all sockets created via socket(2) automatically gains the ID of the thread creating it. Whenever another process touches the socket by either reading or writing to it, we will change the socket classid to that of the process if it has a valid (non-zero) classid. For sockets created on inbound connections through accept(2), we inherit the classid of the original listening socket through sk_clone, possibly preceding the actual accept(2) call. In order to minimise risks, I have not made this the authoritative classid. For now it is only used as a backup when we execute with soft IRQs disabled. Once we're completely happy with its semantics we can use it as the sole classid. Footnote: I have rearranged the error path on cls_group module creation. If we didn't do this, then there is a window where someone could create a tc rule using cls_group before the cgroup subsystem has been registered. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller