Date: Tue, 19 Apr 2005 00:13:52 -0400 From: Mike Tancsa <mike@sentex.net> To: "Adam Kropelin" <akropel1@rochester.rr.com>, <freebsd-usb@freebsd.org> Subject: Re: ugen lockups with apcupsd Message-ID: <6.2.1.2.0.20050418232543.034c5970@64.7.153.2> In-Reply-To: <064001c54481$19ea1b90$03c8a8c0@kroptech.com> References: <6.2.1.2.0.20050418133919.03102d90@64.7.153.2> <064001c54481$19ea1b90$03c8a8c0@kroptech.com>
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At 09:42 PM 18/04/2005, Adam Kropelin wrote:
>Mike Tancsa wrote:
>>Hi,
>> I have been trying out the apcupsd program with an APC
>>RS-1500 on FreeBSD via the ugen interface. On my VIA box, the machine
>>locks up
>>solid within a short period of time after starting the daemon.
>
>This is a known bug and is fixed by a patch I posted to apcupsd-users. The
>BSD UHCI driver has a tendency to leave transfers on the queue when they
>complete 'short' (i.e., with fewer bytes than expected). This happens
>often in apcupsd-3.10.17 due to some poor coding on my part, but can also
>happen on UPSes having broken firmware that sends fewer bytes than the
>report descriptor claims. (These UPSes do not deadlock on Linux, so I
>think there is still a BSD UHCI bug here, but luckily it can be worked
>around in apcupsd.)
Hi, actually, I was just about to post that I found the patches while
looking through the mailing archives and it does seem to fix the issue. I
will let it run overnight to see if it fixes it long term by doing an
apcaccess status once per second in a loop.
I guess this is still kind of a bug as a userland app could potentially DoS
a system no ? One does not need to be root to open the device and
presumably a malicious program could recreate the issue no ?
Thanks again for the code and fix!
---Mike
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