On 15/06/2016 12:00, Xiubo Li wrote:
> These days, we experienced one guest crash with 8 cores and 3 disks,
> with qemu error logs as bellow:
>
> qemu-system-x86_64: /build/qemu-2.0.0/kvm-all.c:984:
> kvm_irqchip_commit_routes: Assertion `ret == 0' failed.
>
> And then we found one patch(bdf026317d) in qemu tree, which said
> could fix this bug.
>
> Execute the following script will reproduce the BUG quickly:
>
> irq_affinity.sh
> ========================================================================
>
> vda_irq_num=25
> vdb_irq_num=27
> while [ 1 ]
> do
> for irq in {1,2,4,8,10,20,40,80}
> do
> echo $irq > /proc/irq/$vda_irq_num/smp_affinity
> echo $irq > /proc/irq/$vdb_irq_num/smp_affinity
> dd if=/dev/vda of=/dev/zero bs=4K count=100 iflag=direct
> dd if=/dev/vdb of=/dev/zero bs=4K count=100 iflag=direct
> done
> done
> ========================================================================
>
> The following qemu log is added in the qemu code and is displayed when
> this bug reproduced:
>
> kvm_irqchip_commit_routes: max gsi: 1008, nr_allocated_irq_routes: 1024,
> irq_routes->nr: 1024, gsi_count: 1024.
>
> That's to say when irq_routes->nr == 1024, there are 1024 routing entries,
> but in the kernel code when routes->nr >= 1024, will just return -EINVAL;
>
> The nr is the number of the routing entries which is in of
> [1 ~ KVM_MAX_IRQ_ROUTES], not the index in [0 ~ KVM_MAX_IRQ_ROUTES - 1].
>
> This patch fix the BUG above.
>
> Signed-off-by: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Wei Tang <tangwei@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Zhang Zhuoyu <zhangzhuoyu@xxxxxxxxxxxxxxxxxxxx>
> ---
> virt/kvm/kvm_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 302681c..a3b5c9b 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2439,7 +2439,7 @@ static long kvm_vm_ioctl(struct file *filp,
> if (copy_from_user(&routing, argp, sizeof(routing)))
> goto out;
> r = -EINVAL;
> - if (routing.nr >= KVM_MAX_IRQ_ROUTES)
> + if (routing.nr > KVM_MAX_IRQ_ROUTES)
> goto out;
> if (routing.flags)
> goto out;
>
Thanks, queued for 4.7-rc.
Paolo
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