Re: [PATCH] PCI: hv: Fix double ida_free in hv_pci_probe error path

[Manivannan Sadhasivam]

On Fri, Apr 03, 2026 at 05:09:29AM -0700, Sahil Chandna wrote:
> If hv_pci_probe() fails after storing the domain number in
> hbus->bridge->domain_nr, there is a call to free this domain_nr via
> pci_bus_release_emul_domain_nr(), however, during cleanup, the bridge
> release callback pci_release_host_bridge_dev() also frees the domain_nr
> causing ida_free to be called on same ID twice and triggering following
> warning:
> 
>   ida_free called for id=28971 which is not allocated.
>   WARNING: lib/idr.c:594 at ida_free+0xdf/0x160, CPU#0: kworker/0:2/198
>   Call Trace:
>    pci_bus_release_emul_domain_nr+0x17/0x20
>    pci_release_host_bridge_dev+0x4b/0x60
>    device_release+0x3b/0xa0
>    kobject_put+0x8e/0x220
>    devm_pci_alloc_host_bridge_release+0xe/0x20
>    devres_release_all+0x9a/0xd0
>    device_unbind_cleanup+0x12/0xa0
>    really_probe+0x1c5/0x3f0
>    vmbus_add_channel_work+0x135/0x1a0
> 
> Fix this by letting pci core handle the free domain_nr and remove
> the explicit free called in pci-hyperv driver.
> 
> Fixes: bcce8c74f1ce ("PCI: Enable host bridge emulation for PCI_DOMAINS_GENERIC platforms")
> Signed-off-by: Sahil Chandna <sahilchandna@xxxxxxxxxxxxxxxxxxx>

Reviewed-by: Manivannan Sadhasivam <mani@xxxxxxxxxx>

Wei: I see that you've taken previous hyperv patches. So feel free to take this
one also.

We will be proactive from next release onwards ;)

- Mani

> ---
>  drivers/pci/controller/pci-hyperv.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index 2c7a406b4ba8..5616ad5d2a8f 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -3778,7 +3778,7 @@ static int hv_pci_probe(struct hv_device *hdev,
>  					   hbus->bridge->domain_nr);
>  	if (!hbus->wq) {
>  		ret = -ENOMEM;
> -		goto free_dom;
> +		goto free_bus;
>  	}
> 
>  	hdev->channel->next_request_id_callback = vmbus_next_request_id;
> @@ -3874,8 +3874,6 @@ static int hv_pci_probe(struct hv_device *hdev,
>  	vmbus_close(hdev->channel);
>  destroy_wq:
>  	destroy_workqueue(hbus->wq);
> -free_dom:
> -	pci_bus_release_emul_domain_nr(hbus->bridge->domain_nr);
>  free_bus:
>  	kfree(hbus);
>  	return ret;
> --
> 2.53.0
> 

-- 
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