On Tue, Sep 01, 2020 at 06:25:42PM +0200, Vitaly Kuznetsov wrote: > Rustam Kovhaev <rkovhaev@xxxxxxxxx> writes: > > > when kmalloc() fails in kvm_io_bus_unregister_dev(), before removing > > the bus, we should iterate over all other devices linked to it and call > > kvm_iodevice_destructor() for them > > > > Reported-and-tested-by: syzbot+f196caa45793d6374707@xxxxxxxxxxxxxxxxxxxxxxxxx > > Link: https://syzkaller.appspot.com/bug?extid=f196caa45793d6374707 > > Signed-off-by: Rustam Kovhaev <rkovhaev@xxxxxxxxx> > > --- > > virt/kvm/kvm_main.c | 7 ++++++- > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index 67cd0b88a6b6..646aa7b82548 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -4332,7 +4332,7 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, > > void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, > > struct kvm_io_device *dev) > > { > > - int i; > > + int i, j; > > struct kvm_io_bus *new_bus, *bus; > > > > bus = kvm_get_bus(kvm, bus_idx); > > @@ -4351,6 +4351,11 @@ void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, > > GFP_KERNEL_ACCOUNT); > > if (!new_bus) { > ^^^ redundant space > > > pr_err("kvm: failed to shrink bus, removing it completely\n"); > > + for (j = 0; j < bus->dev_count; j++) { > > + if (j == i) > > + continue; > > + kvm_iodevice_destructor(bus->range[j].dev); > > + } > > goto broken; > > The name of the label is really misleading (as it is not actually a > failure path), I'd even suggest we get rid of this goto completely, > something like > > new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1), > GFP_KERNEL_ACCOUNT); > if (new_bus) { > memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range)); > new_bus->dev_count--; > memcpy(new_bus->range + i, bus->range + i + 1, > (new_bus->dev_count - i) * sizeof(struct kvm_io_range)); > } else { > pr_err("kvm: failed to shrink bus, removing it completely\n"); > for (j = 0; j < bus->dev_count; j++) { > if (j == i) > continue; > kvm_iodevice_destructor(bus->range[j].dev); > } > > rcu_assign_pointer(kvm->buses[bus_idx], new_bus); > synchronize_srcu_expedited(&kvm->srcu); > kfree(bus); > return; > > > > } > > None of the above should block the fix IMO, so: > > Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > > -- > Vitaly > hi Vitaly, thank you for the review! i'll send the new patch
