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Re: [lwip-users] Possible deadlock in LWIP 1.3.1 RC1
From: |
Kieran Mansley |
Subject: |
Re: [lwip-users] Possible deadlock in LWIP 1.3.1 RC1 |
Date: |
Mon, 24 Aug 2009 09:16:20 +0100 |
On Sun, 2009-08-23 at 15:35 +0300, Eran Rundstein wrote:
> This flow goes on for a while, and then suddenly lwip_write does not
> return - looking at the thread's stack, it is indeed blocking on the
> op_completed semaphore. Nothing seems to signal it - what causes this
> is still a mystery to me.
Sounds like there are two problems here. The first is as described
above, and is probably the more serious. Can you get a packet capture
to illustrate this? Very little has changed since 1.3.1RC1 so I'd be
surprised if this fixed it, but it would be a good idea to check on
current CVS.
> At this stage, I forcefully close the connection from the Linux side.
> This will cause err_tcp() to be called from within the context of LWIP
> thread (tcpip_thread()). err_tcp() first attempts to post data to the
> connection's mbox with:
> if (conn->recvmbox != SYS_MBOX_NULL) {
> /* Register event with callback */
> API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
> sys_mbox_post(conn->recvmbox, NULL);
> }
>
> And afterwards it may or may not signal the completion semaphore. Now,
> sys_mbox_post does not return until the message is posted to the
> queue. Assuming the queue is full, it will not return until a message
> is read from the queue and space is made available.
This second problem seems a bit more straightforward. We need some way
to postpone the addition to the recvmbox if the mbox is full, or change
the mbox so that NULL can always be posted. I prefer the latter.
Either way, could you file a bug for this part of the problem?
- [lwip-users] Possible deadlock in LWIP 1.3.1 RC1, Eran Rundstein, 2009/08/23
- Re: [lwip-users] Possible deadlock in LWIP 1.3.1 RC1,
Kieran Mansley <=
- [lwip-users] IP Address Display Functions, Chris Strahm, 2009/08/24
- Re: [lwip-users] IP Address Display Functions, address@hidden, 2009/08/24
- RE: [lwip-users] IP Address Display Functions, Bill Auerbach, 2009/08/24
- Re: [lwip-users] IP Address Display Functions, Mandeep Sandhu, 2009/08/25
- Re: [lwip-users] IP Address Display Functions, Kieran Mansley, 2009/08/25
- RE: [lwip-users] IP Address Display Functions, Bill Auerbach, 2009/08/25
- RE: [lwip-users] IP Address Display Functions, Kieran Mansley, 2009/08/25
- RE: [lwip-users] IP Address Display Functions, Kieran Mansley, 2009/08/25
- RE: [lwip-users] IP Address Display Functions, Kieran Mansley, 2009/08/25
- [lwip-users] Re: IP Address Display Functions, Jakob Stoklund Olesen, 2009/08/25