Re: PPP is not SMP safe in 2.2.X, Oops

From: Rik van Riel (riel@nl.linux.org)
Date: Mon Feb 07 2000 - 11:04:35 EST


On Mon, 7 Feb 2000, Mitchell Blank Jr wrote:
> Oleg Drokin wrote:
> > It seems PPP is not SMP safe in 2.2.X
>
> Hmmm... looks like you're right. Someone is stepping on ppp->tpkt in between
> the time ppp_tty_push called ppp_async_encode and it was done with the packet.
>
> ppp_tty_flush_output - seems unlikely. I don't know if its actually SMP
> safe, but you're probably not getting flushes
> ppp_async_release - could be... does this happen perchance when a connection
> is being closed?
> another ppp_tty_push - uh, I really hope ppp->tty_pushing isn't the only
> thing serializing access here.. that doesn't look healthy to me.

The tty code in 2.2 (and 2.3) isn't SMP safe either.
SMP Linux seems to have some serious problems performing
character I/O :(

regards,

Rik

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