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sctp: avoid irq lock inversion while call sk->sk_data_ready()

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sk->sk_data_ready() of sctp socket can be called from both BH and non-BH
contexts, but the default sk->sk_data_ready(), sock_def_readable(), can
not be used in this case. Therefore, we have to make a new function
sctp_data_ready() to grab sk->sk_data_ready() with BH disabling.

=========================================================
[ INFO: possible irq lock inversion dependency detected ]
2.6.33-rc6 #129
---------------------------------------------------------
sctp_darn/1517 just changed the state of lock:
 (clock-AF_INET){++.?..}, at: [<c06aab60>] sock_def_readable+0x20/0x80
but this lock took another, SOFTIRQ-unsafe lock in the past:
 (slock-AF_INET){+.-...}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
1 lock held by sctp_darn/1517:
 #0:  (sk_lock-AF_INET){+.+.+.}, at: [<cdfe363d>] sctp_sendmsg+0x23d/0xc00 [sctp]

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wei Yongjun 2010-04-28 08:47:18 +00:00 committed by David S. Miller
parent 8d238b25b1
commit 561b1733a4
3 changed files with 12 additions and 0 deletions
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1
include/net/sctp/sctp.h
View File

@ -128,6 +128,7 @@ extern int sctp_register_pf(struct sctp_pf *, sa_family_t);
int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
int sctp_inet_listen(struct socket *sock, int backlog);
void sctp_write_space(struct sock *sk);
void sctp_data_ready(struct sock *sk, int len);
unsigned int sctp_poll(struct file *file, struct socket *sock,
poll_table *wait);
void sctp_sock_rfree(struct sk_buff *skb);

1
net/sctp/endpointola.c
View File

@ -144,6 +144,7 @@ static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
/* Use SCTP specific send buffer space queues. */
ep->sndbuf_policy = sctp_sndbuf_policy;
sk->sk_data_ready = sctp_data_ready;
sk->sk_write_space = sctp_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);

10
net/sctp/socket.c
View File

@ -6189,6 +6189,16 @@ do_nonblock:
goto out;
}
void sctp_data_ready(struct sock *sk, int len)
{
read_lock_bh(&sk->sk_callback_lock);
if (sk_has_sleeper(sk))
wake_up_interruptible_sync_poll(sk->sk_sleep, POLLIN |
POLLRDNORM | POLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
read_unlock_bh(&sk->sk_callback_lock);
}
/* If socket sndbuf has changed, wake up all per association waiters. */
void sctp_write_space(struct sock *sk)
{