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Date: Mon, 20 Dec 2004 21:29:52 -0700 (MST)
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To: steve@Watt.COM
From: "M. Warner Losh" <imp@bsdimp.com>
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cc: freebsd-usb@freebsd.org
Subject: Re: panic w/ USB<->serial adapter and modem
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In message: <200412190252.iBJ2q1eW002380@wattres.watt.com>
            steve@Watt.COM (Steve Watt) writes:
: So it's pretty clear, reading that over, that uhci_abort_xfer
: *IS* being called from interrupt context, namely when carrier
: drops.  There's some kind of think-o happening in there, but
: I'm not sure quite what to do about it.
: 
: It also looks like there's some risk of ugly recursion, because
: usb_transfer_complete is called from uhci_abort_xfer, but I really
: haven't analyzed the code path well enough to be certain that
: it's OK.

Hmmm, that's generally not supposed to be possible, but with FreeBSD's
stack it is.  I have changes to queue everything to a taskqueue.
Maybe those would help...

Warner