Messages in this thread | | | Date | Wed, 26 Nov 2014 07:52:56 +0100 | From | Juergen Gross <> | Subject | Re: frequent lockups in 3.18rc4 |
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On 11/26/2014 07:21 AM, Linus Torvalds wrote: > On Tue, Nov 25, 2014 at 9:52 PM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: >> >> And leave it running for a while, and see if the trace is always the >> same, or if there are variations on it... > > Amusing. > > Lookie here: > > http://lists.xenproject.org/archives/html/xen-changelog/2005-08/msg00310.html > > That's from 2005.
:-)
> > Anyway, I don't see why the cr3 issue matters, *unless* there is some > situation where the scheduler can run with interrupts enabled. And why > this is Xen-related, I have no idea. > > The Xen patches seem to have lost that > > /* On Xen the line below does not always work. Needs investigating! */ > > line when backporting the 2.6.29 patches to Xen. And clearly nobody > investigated. > > So please do get me back-traces, and we'll investigate. Better late > than never. But it does sound Xen-specific - although it's possible > that Xen just triggers some timing (and has apparently been able to > trigger it since 2005) that DaveJ now triggers on his one machine.
Yeah, this sounds plausible.
I'm working on the back traces right now, hope to have them soon.
Juergen
> > So DaveJ, even though this does appear Xen-centric (Xentric?) and > you're running on bare hardware, maybe you could do the same thing in > that x86-64 vmalloc_fault(). The timing with Jürgen is kind of > intriguing - if 3.18-rc made it happen much more often for him, maybe > it really is very timing-sensitive, and you actually are seeing a > non-Xen version of the same thing... > > Linus >
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