[ECOS] simultaneous socket write/close causes panic?
Tue Nov 5 07:46:00 GMT 2002
On Tue, Nov 05, 2002 at 05:17:37AM +0000, Jonathan Larmour wrote:
> Just to summarise: the application is almost certainly broken
> because it shouldn't do stuff like this because the socket fd
> number may be reallocated (modulo micromanagement of the code
> so you could guarantee that it wouldn't be).
Yes. Perhaps the customer is doing that sort of management,
but I'd still claim it's broken code.
> The stack is
> *also* broken as it shouldn't panic.
> Nick Garnett wrote:
> > I would contend that the locking regime in the TCP/IP stack is at
> > present not right and needs to be fixed.
> Potentially, or more accurately Grant should use the new
> FreeBSD stack :-).
Probably so. It would require adding the fileio package also.
If I had a spare day or two...
Are there noticable performance differences between the two
stacks? We're running out of horsepower in our ARM7 app with
lots of TCP/IP connections running. If the new stack required
fewer memcpy() operations it would be a huge win. My Ethernet
does DMA but not scatter gather, so having the Tx packets
presented to me in chunks is a big performance hit.
> Anyway, Hugo did a lot of work in this area at one point.
> Grant, you said the code was from an eCos and net snapshot from
> Jan 2001. Even so, does it definitely have this change:
> 2000-09-01 Hugo Tyson <email@example.com>
> * OVERVIEW: This is part of the change to the network stack to
Yes. My tcpip ChangeLog goes up through:
2000-11-15 Hugo Tyson <firstname.lastname@example.org>
* src/lib/bootp_support.c (init_net): Do a SIOCSIFADDR a 2nd time
after setting the netmask (SIOCSIFNETMASK) in order for the newly
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