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Re: net: splsoftnet - problems
- To: jtroeger at nortelnetworks dot com
- Subject: Re: [ECOS] net: splsoftnet - problems
- From: Bart Veer <bartv at redhat dot com>
- Date: Fri, 18 Aug 2000 12:51:56 +0100
- CC: ecos-discuss at sources dot redhat dot com
- References: <004b01c008ff$b1098e10$24313fc3@jtpc>
- Reply-to: bartv at redhat dot com
>>>>> "Joerg" == Joerg Troeger <jtroeger@nortelnetworks.com> writes:
Joerg> SSBoYXZlIHNvbWUgY29uY2VybnMgcmVsYXRlZCB0byB0aGUgInNwbHNvZnRuZ
Joerg> b24gb2YgdGhlIFRDUC9JUCBzdGFjay4NCg0KMS4gc3Bsc29mdG5ldCBtYXkgY
...
Please set up your mailer to send in plain text, not in MIME. Not
everybody uses mime-aware mail readers, so such messages may well get
ignored by the people who would be able to answer. In this case I'll
make sure that the relevant engineer sees both your postings,
decrypted.
Joerg> I have some concerns related to the "splsoftnet()" function
Joerg> of the TCP/IP stack.
Joerg> 1. splsoftnet may block due to cyg_mutex_lock() - but is
Joerg> called in the context of the real-time-clock DSR
Joerg> (tcp_fasttimo, tcp_slowtimo).
Joerg> 2. splsoftnet may try to lock a mutex twice!! Consider a
Joerg> timer interrupt right after calling
Joerg> "cyg_mutex_loc(&softnet_mutex)" and before returning from
Joerg> "cyg_scheduler_lock()" - it est between line #246 and #247
Joerg> of support.c rev. 1.5. The timer interrupt may call
Joerg> tcp_fasttimo, which calls splsoftnet - which tries to lock
Joerg> the same mutex once more (this has been seen happen!).
Joerg> I am quiet not sure how to solve this problems and would be
Joerg> glad if this can be commented!
Officially the TCP/IP stack is still in beta, there are still some
problems which are being resolved. I know that there were some changes
to the timeout.c and support.c files just yesterday, which may or may
not relate to the issues you have raised. The next anoncvs snapshot
should contain those and other changes.
Of course any help we get in sorting out the remaining problems will
be greatly appreciated.
There is a slight complication in that anoncvs updates have been
suspended for a little while, to restabilize the tree after some major
changes. They should start again real soon now (as in days, not
weeks).
Bart Veer // eCos net maintainer