Messages in this thread | | | Date | Tue, 02 Apr 2002 17:35:52 +0530 | From | "Madhavan N.S." <> | Subject | Frame Relay stack on Linux |
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Hi,
We are developing Frame Relay stack on Linux 2.4 kernel. It's implemented as a dynamically loadable software module and it is registered as a network driver. Frame Relay module uses the services of lower layer hardware driver module for transmission & reception of data packets.
Working of Frame Relay stack:
FR task is initiated after loading the module using socket ioctl interface. Once initiated FR task goes to sleep waiting for events. It uses interruptible_sleep_on kernel function.
There can be 3 different events which can wake up the FR task.
1. When the Frame Relay NIC gets packet from network ,lower driver process it as part of interrupt processing and wake up the FR task using wake_up_interruptible kernel function. FR task will process the packet and call netif_rx function to give the packet to IP layer.
2. When IP layer sends packet through FR stack it invokes Frame Relay transmit function which will wake up the FR task using wake_up_interruptible kernel function. FR task will process it and send it using lower hardware driver.
3. After transmitting the packet FR NIC card interrupts the lower driver which will again wake up the FR task using wake_up_interruptible kernel function. This indicates transmit completion to the FR task and it schedules next packet to be transmitted.
After processing the event FR task again go back to the main loop again waiting for events.
Problem Description :
FR stack is crashing when TELNET/FTP application is run. It's crashing on the server side i.e., machine which accepts the connection.
It panics when FR task goes to sleep (by calling interruptible_sleep_on function ) after calling netif_rx fuction. This kernel function in turn calls schedule() and while executing schdule() function do_page_fault() is getting invoked and system panics.
But PING through FR stack is working absolutely fine. We have written socket application program for data transfer through FR stack. For UDP socket (SOCK_DGRAM) data transfer goes fine , but when data transfer goes through TCP socket (SOCK_STREAM) it panics at the same place as when we run telnet/ftp application i.e., in schedule function.
For testing the stack Uniprocessor machine is used. Can anyone help me to solve this problem?
Please do CC to madhavan.nair@wipro.com as I have not registered in the Mailing List.
Madhavan
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