Messages in this thread | | | Date | Wed, 26 Nov 2014 05:39:06 +0100 | From | Jürgen Groß <> | Subject | Re: frequent lockups in 3.18rc4 |
| |
On 11/26/2014 02:48 AM, Linus Torvalds wrote: > On Tue, Nov 25, 2014 at 4:25 PM, Dave Jones <davej@redhat.com> wrote: >> >> The reason I'm checking in at this point, is that I'm starting to see different >> bugs at this point, so I don't know if I can call this good or bad, unless >> someone has a fix for what I'm seeing now. > > Hmm. The three last "bad" biisects are all just 3.17-rc1 plus staging fixes. > >> Reminiscent of a bug a couple releases ago. Processes about to exit, but stuck >> in the kernel continuously faulting.. >> http://codemonkey.org.uk/junk/weird-hang.txt >> The one I'm thinking of got fixed way before 3.17 though. > > Well, the staging tree was based on that 3.17-rc1 tree, so it may well > have the bug without the fix. > > You have also marked 3.18-rc1 bad *twice*, along with the network > merge, and the tty merge. That's just odd. But it doesn't make the > bisect wrong, it just means that you fat-fingered thing and marked the > same thing bad a couple of times. > > Nothing to worry about, unless it's a sign of early Parkinsons... > >> Does that trace ring a bell of something else I could try on top of >> each bisection point ? > > Hmm. > > Smells somewhat like the "pipe/page fault oddness" bug you reported. > > That one caused endless page faults on fault_in_pages_writeable() > because of a page table entry that the VM thought was present, but the > CPU thought was missing. > > That caused the whole "pte_protnone()" thing, and trying to get rid of > the PTE_NUMA bit, but those patches have *not* been merged. And you > were ever able to reproduce it., so we left it as pending. > > But if you actually really think that the bisect log you posted is > real and true and actually is the bug you're chasing, I have bad news > for you: do a "gitk --bisect", and you'll see that all the remaining > commits are just to staging drivers. > > So that would either imply you have some staging driver (unlikely), or > more likely that 3.17 really already has the problem, it's just that > it needs some particular code alignment or phase of the moon or > something to trigger.
I COULD trigger it with 3.17. Took much longer, but I've seen it once. And from Xen hypervisor data it was clear it was the same bug (cpu spinning in pmd_lock()).
Juergen
| |