Re: [RFC PATCH] virtio_blk: Checking "private_data" to avoid kernelpanic when hotplugging

From: Michael S. Tsirkin
Date: Mon Apr 09 2012 - 03:56:10 EST


On Wed, Mar 28, 2012 at 11:40:33AM +0800, Ren Mingxin wrote:
> Hi,
>
> On guest with upstream's kernel(3.3.0-rc7), I
> mounted virtblk as:
> a) # mkfs /dev/vda
> b) # mount /dev/vda /mnt
> c) # cd /mnt
>
> Then I did hotplug for virtblk via virsh on host as:
> a) # sudo virsh detach-disk guest vda
> b) # sudo virsh attach-disk guest /media/data/test.img vda
>
> I encountered guest's kernel panic (*probability *
> *event*)whose backtrace liked this:

Any news here? Managed to trace?
Does this still happen with 3.4-rc2?
There's a chance you are hitting a race fixed by
4678d6f970c2f7c0cbfefc0cc666432d153b321b.

If it's still not fixed it might make sense to enable slab debugging -
we might have a use after free here.

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