> From: gregkh@xxxxxxxxxxxxxxxxxxx <gregkh@xxxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, May 15, 2019 1:35 AM
> To: Dexuan Cui <decui@xxxxxxxxxxxxx>; lorenzo.pieralisi@xxxxxxx; Michael
> Kelley <mikelley@xxxxxxxxxxxxx>; stephen@xxxxxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx
> Subject: FAILED: patch "[PATCH] PCI: hv: Fix a memory leak in
> hv_eject_device_work()" failed to apply to 4.9-stable tree
>
>
> The patch below does not apply to the 4.9-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From 05f151a73ec2b23ffbff706e5203e729a995cdc2 Mon Sep 17 00:00:00
> 2001
> From: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Date: Mon, 4 Mar 2019 21:34:48 +0000
> Subject: [PATCH] PCI: hv: Fix a memory leak in hv_eject_device_work()
>
> When a device is created in new_pcichild_device(), hpdev->refs is set
> to 2 (i.e. the initial value of 1 plus the get_pcichild()).
>
> When we hot remove the device from the host, in a Linux VM we first call
> hv_pci_eject_device(), which increases hpdev->refs by get_pcichild() and
> then schedules a work of hv_eject_device_work(), so hpdev->refs becomes
> 3 (let's ignore the paired get/put_pcichild() in other places). But in
> hv_eject_device_work(), currently we only call put_pcichild() twice,
> meaning the 'hpdev' struct can't be freed in put_pcichild().
>
> Add one put_pcichild() to fix the memory leak.
>
> The device can also be removed when we run "rmmod pci-hyperv". On this
> path (hv_pci_remove() -> hv_pci_bus_exit() -> hv_pci_devices_present()),
> hpdev->refs is 2, and we do correctly call put_pcichild() twice in
> pci_devices_present_work().
>
> Fixes: 4daace0d8ce8 ("PCI: hv: Add paravirtual PCI front-end for Microsoft
> Hyper-V VMs")
> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> [lorenzo.pieralisi@xxxxxxx: commit log rework]
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Reviewed-by: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
>
> diff --git a/drivers/pci/controller/pci-hyperv.c
> b/drivers/pci/controller/pci-hyperv.c
> index 95441a35eceb..30f16b882746 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -1900,6 +1900,9 @@ static void hv_eject_device_work(struct work_struct
> *work)
> sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
> VM_PKT_DATA_INBAND, 0);
>
> + /* For the get_pcichild() in hv_pci_eject_device() */
> + put_pcichild(hpdev);
> + /* For the two refs got in new_pcichild_device() */
> put_pcichild(hpdev);
> put_pcichild(hpdev);
> put_hvpcibus(hpdev->hbus);
Hi,
I backported the patch for linux-4.9.y. Please use the attached patch.
Thanks,
-- Dexuan
Attachment:
For-linux-4.9.y_v4.9.176_PCI-hv-Fix-a-memory-leak-in-hv_eject_device_work.patch
Description: For-linux-4.9.y_v4.9.176_PCI-hv-Fix-a-memory-leak-in-hv_eject_device_work.patch
