Re: [sched/preempt] INFO: rcu_sched self-detected stall on CPU { 1}

From: Bockholdt Arne
Date: Fri Feb 07 2014 - 02:12:13 EST


On Thu, 2014-02-06 at 13:19 +0100, Peter Zijlstra wrote:
> On Thu, Feb 06, 2014 at 12:08:54PM +0000, Bockholdt Arne wrote:
> > This on a a Intel Rangeley Silvermont Atom 8 core machine running kernel
> > 3.13.1/i386 as KVM host with several KVM guests. Tested with the same
> > configuration on kernel 3.12.9 and 3.11.6 without the stall. The stall
> > is 100% reproducible when the KVM guests are under load.
> > Kernel 3.13.1 does NOT contain the patch below AFAIK.
>
> 3.13 doesn't include 8cb75e0c4ec9786b81439761eac1d18d4a931af3 either.
>
> can you try a recent linux.git? Also, can you test with a 64bit kernel
> too?


The machine isn't exactly a test box but I've tried to run the latest Linus 3.14-rc git and got an error about a symbol version mismatch (see below). I will try it again at the weekend when there is more time for tests like this.

Feb 6 21:25:45 kvm-server kernel: [ 3.479594] usbhid: disagrees about version of symbol schedule_timeout
Feb 6 21:25:45 kvm-server kernel: [ 3.479599] usbhid: Unknown symbol schedule_timeout (err -22)
Feb 6 21:25:45 kvm-server kernel: [ 3.479819] usbhid: disagrees about version of symbol schedule_timeout
Feb 6 21:25:45 kvm-server kernel: [ 3.479823] usbhid: Unknown symbol schedule_timeout (err -22)
Feb 6 21:25:45 kvm-server kernel: [ 3.668097] EXT4-fs (sdc1): mounted filesystem with ordered data mode. Opts: (null)
Feb 6 21:25:45 kvm-server kernel: [ 3.884211] random: init urandom read with 84 bits of entropy available
Feb 6 21:25:45 kvm-server kernel: [ 4.180695] random: nonblocking pool is initialized
Feb 6 21:25:45 kvm-server kernel: [ 4.213268] EXT4-fs (sdc1): re-mounted. Opts: errors=remount-ro,discard
Feb 6 21:25:45 kvm-server kernel: [ 4.262349] i801_smbus 0000:00:1f.3: SMBus using PCI Interrupt
Feb 6 21:25:45 kvm-server kernel: [ 4.282062] ismt_smbus 0000:00:13.0: irq 53 for MSI/MSI-X
Feb 6 21:25:45 kvm-server kernel: [ 4.289796] pps_core: disagrees about version of symbol schedule_timeout
Feb 6 21:25:45 kvm-server kernel: [ 4.289803] pps_core: Unknown symbol schedule_timeout (err -22)
Feb 6 21:25:45 kvm-server kernel: [ 4.292363] pps_core: disagrees about version of symbol schedule_timeout

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