On 16-11-2011 16:33, Alexander Motin wrote: > On 11/16/11 16:14, Bjoern A. Zeeb wrote: > > On Wed, 16 Nov 2011, Alexander Motin wrote: > > > >> Hi. > >> > >> On 11/16/11 08:43, Bjoern A. Zeeb wrote: > >>> we have seen this or a very similar panic for about 1 year now once in > >>> a while and I think I reported it before; this is FreeBSD as guest on > >>> vmware. Seems it was a double panic this time. Could someone please > >>> see what's going on there? It was on 8.x-STABLE in the past and this > >>> is 8.2-RELEASE-p4. > >> > >> The part of code reporting "completing request directly" is IMHO broken > >> by design. It returns request completion before request will actually be > >> completed by lower levels without any knowledge of what's going on > >> there. There is kind of protection against double request completion, > >> but it looks like not always working. May be because that part of code > >> is not locked and nothing prevents that semaphore timeout and normal > >> request timeout/completion to happen simultaneously. It is surprising to > >> see even two traps same time, not sure what synchronized them so > >> precisely. > >> > >> Simple removing that semaphore timeout is not an option, because it will > >> cause deadlock when this wait happen within taskqueue thread that is > >> used to handle requests completion and abort that wait. Avoid waiting > >> inside taskqueue is also impossible without major rewrite. That's why > >> ATA_CAM drops that code completely. > > > > So the bottom line of what you are saying is: > > 1) it's hard to fix right in 8 > > 2) it's not an issue in 9 anymore at all? > > Right.
Hmm. We're running many FreeBSD 8.2 machines as guests in VMware but have never encountered the panic described above. Should I be worried? :-) -- Joel _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
