Panic with usb serial

M. Warner Losh imp at
Sat Mar 29 18:17:14 PDT 2008

In message: <20080329222049.GA80263 at>
            Jeremy Chadwick <koitsu at> writes:
: On Sat, Mar 29, 2008 at 10:11:04PM +0000, Vince wrote:
: > 	Is it expected that removing a usb serial adapter while you have a 
: > connection (eg tip) using it will panic a -stable system? I know it is 
: > expected if you remove a mounted umass device so wanted to see if its known 
: > behavior for serial before I file a pr. (adapter is <FTDI usb serial 
: > converter, class 0/0, rev 1.10/4.00, addr 3>)
: > -stable version as of the 25th march, (may have existed before but the 
: > first time I forgot to close tip before removing the device was on this 
: > version.)
: I would expect that the problem is identical in the sense that with a
: connection established, you have an open file descriptor which is
: associated with a serial device that uses USB.
: So, yes, I would expect this behaviour based on the track record.
: Should it happen?  The answer is no.  File a PR?
: Also, I'd like to know what USB serial adapter you're using (brand,
: model, and a website of it if possible), for unrelated reasons.  Thanks!

That's odd, because I use an FTDI based serial device all the time for
hacking on embedded systems.  The problem that I have is 100% CPU
usage on a tip process until I kill it.


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