mikem@xn.ll.mit.edu (Michael Maciolek) (04/25/89)
Could someone enlighten me (or refer me to some enlightening back-issues of sun-spots) as to the general origin of the classic "panic: mget" error message? I'd like a general understanding of what an "mget" is trying to do, and why it might panics. We are running SL/IP on a 3/160 running SunOS 3.5. We didn't seem to have any trouble with panic:mget until we also installed a Tektronics interface board for their 4693D color printer. ALSO: Is there a publicly-accessible source for a SunOS 4.0 version of SL/IP? [[ Yes, in the Rice archives. It is under "sun-source" and is called "slip4.0.shar". It can be retrieved via anonymous FTP from the host "titan.rice.edu" or via the archive server. For more information about the archive server, send a mail message containing the word "help" to the address "archive-server@rice.edu". --wnl ]] Any suggestions for tracking down the source of the panics would be appreciated. Send email to mikem@juliet.ll.mit.edu (preferred) or mikem@ll-xn.arpa.uucp
smb@arpa.att.com (05/06/89)
The networking code uses a pool of buffers called mbufs; mget obtains a free buffer. Locking for access to the buffer pool is done by calling splimp(), which is supposed to be higher than any network device can interrupt. I think that some serial boards interrupt at a higher priority than this, and -- since SLIP runs on serial lines -- you can get into trouble. You can either restrap your serial board to a lower priority, or -- if you're skillful with adb -- you can patch the splimp() code to be a higher mask.
pratt@triangle.com (05/06/89)
In Sun-Spots v7n244 Michael Maciolek writes Could someone enlighten me (or refer me to some enlightening back-issues of sun-spots) as to the general origin of the classic "panic: mget" error message? I'd like a general understanding of what an "mget" is trying to do, and why it might panics. We are running SL/IP on a 3/160 running SunOS 3.5. We didn't seem to have any trouble with panic:mget until we also installed a Tektronics interface board for their 4693D color printer. We're having the same problem, but with slip4.0 on a Sun-4 under 4.0.1 and with the offending widget possibly being either an ALM-2 or (an interface to) MTU's Digisound-16. Rayan Zachariassen says it is probably due to slip being interrupted during an mget, and that the driver should be modified so that slip_rput queues everything to a service routine. Sounds like it may apply to 3.x slip as well. Small matter of finding someone to do it. Vaughan Pratt pratt@triangle.com