| From | Willy Tarreau <> | Subject | [PATCH 3.10 120/180] kvm: Fix irq route entries exceeding KVM_MAX_IRQ_ROUTES | Date | Sun, 21 Aug 2016 17:30:50 +0200 |
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From: Xiubo Li <lixiubo@cmss.chinamobile.com>
commit caf1ff26e1aa178133df68ac3d40815fed2187d9 upstream.
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.
Cc: stable@vger.kernel.org Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Wei Tang <tangwei@cmss.chinamobile.com> Signed-off-by: Zhang Zhuoyu <zhangzhuoyu@cmss.chinamobile.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Willy Tarreau <w@1wt.eu> --- 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 4f865e1..f71c4ad 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2447,7 +2447,7 @@ 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; -- 2.8.0.rc2.1.gbe9624a
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