В Пт, 29/05/2015 в 17:20 +0300, Andrew Vagin пишет:
> Acked-by: Andrew Vagin <ava...@odin.com>
>
> I'm agree that we need to remove this function, but I don't know how it
> fixes the bug.
tcp_v4_kill_ve_sockets() is called when all processes are killed,
and their sockets have been already replaced with time wait sockets.
So, when we are iterating through chain list:
sk_nulls_for_each(sk, node, &head[i].chain)
we can't find TCP sockets there. Every sk is of type inet_timewait_sock.
Yes, they both are linked in the same table.
struct sock (tcp_sock) and inet_timewait_sock are not a child and a parent:
struct sock { struct inet_timewait_sock {
struct sock_common __sk_common; struct sock_common __tw_common;
socket_lock_t sk_lock; int tw_timeout;
They are different.
So, when we are doing bh_lock_sock(sk) in tcp_v4_kill_ve_sockets(), i.e.
#define bh_lock_sock(__sk) spin_lock(&((__sk)->sk_lock.slock))
we are trying to manipulate with tw_timeout, which is not zero, and can't
acquire the spinlock.
> On Fri, May 29, 2015 at 04:53:39PM +0300, Kirill Tkhai wrote:
> > This is a leftover from earlier versions of PCS,
> > and we do not need that functionality in 3.10.
> >
> > It was the reason of the kernel panic in 2.6.32:
> > https://jira.sw.ru/browse/PSBM-33755, in the test
> > of forced CT destroying.
> >
> > Also, tcp_v4_kill_ve_sockets() looks as the only
> > user of synchronize_net(), so we're not need this
> > function too (the only net hook fini_venet_acct_ip6_stat()
> > from the chain doesn't need it). Besides this, there
> > will be one more synchronize_rcu() later in
> > ve_drop_context().
> >
> > Signed-off-by: Kirill Tkhai <ktk...@odin.com>
> > ---
> > include/linux/ve_proto.h | 5 +--
> > kernel/ve/ve.c | 5 +--
> > net/ipv4/tcp_ipv4.c | 88
> > ----------------------------------------------
> > 3 files changed, 2 insertions(+), 96 deletions(-)
> >
> > diff --git a/include/linux/ve_proto.h b/include/linux/ve_proto.h
> > index d491ab0..e77d6f9 100644
> > --- a/include/linux/ve_proto.h
> > +++ b/include/linux/ve_proto.h
> > @@ -50,12 +50,9 @@ typedef void (*ve_seq_print_t)(struct seq_file *, struct
> > ve_struct *);
> > void vzmon_register_veaddr_print_cb(ve_seq_print_t);
> > void vzmon_unregister_veaddr_print_cb(ve_seq_print_t);
> >
> > -#ifdef CONFIG_INET
> > -void tcp_v4_kill_ve_sockets(struct ve_struct *envid);
> > -#ifdef CONFIG_VE_NETDEV
> > +#if defined(CONFIG_INET) && defined(CONFIG_VE_NETDEV)
> > int venet_init(void);
> > #endif
> > -#endif
> >
> > extern struct list_head ve_list_head;
> > #define for_each_ve(ve) list_for_each_entry((ve), &ve_list_head,
> > ve_list)
> > diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
> > index 55b7d86..3128fdb 100644
> > --- a/kernel/ve/ve.c
> > +++ b/kernel/ve/ve.c
> > @@ -647,10 +647,7 @@ void ve_exit_ns(struct pid_namespace *pid_ns)
> >
> > down_write(&ve->op_sem);
> > ve_hook_iterate_fini(VE_SS_CHAIN, ve);
> > -#ifdef CONFIG_INET
> > - tcp_v4_kill_ve_sockets(ve);
> > - synchronize_net();
> > -#endif
> > +
> > ve_list_del(ve);
> > ve_drop_context(ve);
> > up_write(&ve->op_sem);
> > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> > index ad4520c..a8ef57a 100644
> > --- a/net/ipv4/tcp_ipv4.c
> > +++ b/net/ipv4/tcp_ipv4.c
> > @@ -2812,91 +2812,3 @@ void __init tcp_v4_init(void)
> > if (register_pernet_subsys(&tcp_sk_ops))
> > panic("Failed to create the TCP control socket.\n");
> > }
> > -
> > -#ifdef CONFIG_VE
> > -static void tcp_kill_ve_onesk(struct sock *sk)
> > -{
> > - struct tcp_sock *tp = tcp_sk(sk);
> > -
> > - /* Check the assumed state of the socket. */
> > - if (!sock_flag(sk, SOCK_DEAD)) {
> > - printk(KERN_WARNING "Killing sk: dead %d, state %d, "
> > - "wrseq %u unseq %u, wrqu %d.\n",
> > - sock_flag(sk, SOCK_DEAD), sk->sk_state,
> > - tp->write_seq, tp->snd_una,
> > - !skb_queue_empty(&sk->sk_write_queue));
> > - sk->sk_err = ECONNRESET;
> > - sk->sk_error_report(sk);
> > - }
> > -
> > - tcp_send_active_reset(sk, GFP_ATOMIC);
> > - switch (sk->sk_state) {
> > - case TCP_FIN_WAIT1:
> > - case TCP_CLOSING:
> > - /* In these 2 states the peer may want us to retransmit
> > - * some data and/or FIN. Entering "resetting mode"
> > - * instead.
> > - */
> > - tcp_time_wait(sk, TCP_CLOSE, 0);
> > - break;
> > - case TCP_FIN_WAIT2:
> > - /* By some reason the socket may stay in this state
> > - * without turning into a TW bucket. Fix it.
> > - */
> > - tcp_time_wait(sk, TCP_FIN_WAIT2, 0);
> > - break;
> > - default:
> > - /* Just jump into CLOSED state. */
> > - tcp_done(sk);
> > - break;
> > - }
> > -}
> > -
> > -void tcp_v4_kill_ve_sockets(struct ve_struct *envid)
> > -{
> > - struct inet_ehash_bucket *head;
> > - int i, retry;
> > -
> > - /* alive */
> > -again:
> > - retry = 0;
> > - local_bh_disable();
> > - head = tcp_hashinfo.ehash;
> > - for (i = 0; i < tcp_hashinfo.ehash_mask; i++) {
> > - struct sock *sk;
> > - struct hlist_nulls_node *node;
> > - spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, i);
> > -more_work:
> > - spin_lock(lock);
> > - sk_nulls_for_each(sk, node, &head[i].chain) {
> > - if (sock_net(sk)->owner_ve == envid) {
> > - sock_hold(sk);
> > - spin_unlock(lock);
> > -
> > - bh_lock_sock(sk);
> > - if (sock_owned_by_user(sk)) {
> > - retry = 1;
> > - bh_unlock_sock(sk);
> > - sock_put(sk);
> > - goto enable_bh;
> > - }
> > - /* sk might have disappeared from the hash
> > before
> > - * we got the lock */
> > - if (sk->sk_state != TCP_CLOSE)
> > - tcp_kill_ve_onesk(sk);
> > - bh_unlock_sock(sk);
> > - sock_put(sk);
> > - goto more_work;
> > - }
> > - }
> > - spin_unlock(lock);
> > - }
> > -enable_bh:
> > - local_bh_enable();
> > - if (retry) {
> > - schedule_timeout_interruptible(HZ);
> > - goto again;
> > - }
> > -}
> > -EXPORT_SYMBOL(tcp_v4_kill_ve_sockets);
> > -#endif
> >
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