RE: FAILED: patch "[PATCH] PCI: hv: Fix a memory leak in hv_eject_device_work()" failed to apply to 4.14-stable tree

[Dexuan Cui <decui@microsoft.com>]

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> From: gregkh@linuxfoundation.org <gregkh@linuxfoundation.org>
> Sent: Wednesday, May 15, 2019 1:35 AM
> To: Dexuan Cui <decui@microsoft.com>; lorenzo.pieralisi@arm.com; Michael
> Kelley <mikelley@microsoft.com>; stephen@networkplumber.org
> Cc: stable@vger.kernel.org
> Subject: FAILED: patch "[PATCH] PCI: hv: Fix a memory leak in
> hv_eject_device_work()" failed to apply to 4.14-stable tree
> 
> 
> The patch below does not apply to the 4.14-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@vger.kernel.org>.
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From 05f151a73ec2b23ffbff706e5203e729a995cdc2 Mon Sep 17 00:00:00
> 2001
> From: Dexuan Cui <decui@microsoft.com>
> 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@microsoft.com>
> [lorenzo.pieralisi@arm.com: commit log rework]
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
> Reviewed-by:  Michael Kelley <mikelley@microsoft.com>
> Cc: stable@vger.kernel.org
> 
> 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-4.14.y.

Please use the attached patch, which is [PATCH 1/3]

Thanks,
-- Dexuan

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From 16cce286be5af8e3d59c9afb74a494493254dcd3 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <decui@microsoft.com>
Date: Wed, 15 May 2019 15:42:07 -0700
Subject: [PATCH for v4.14.119 1/3] PCI: hv: Fix a memory leak in
 hv_eject_device_work()

This patch is backported for v4.14.119 from the mainline
commit 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()")

Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
 drivers/pci/host/pci-hyperv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 53d1c08cef4d..292450c7da62 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -1941,6 +1941,7 @@ static void hv_eject_device_work(struct work_struct *work)
 			 VM_PKT_DATA_INBAND, 0);
 
 	put_pcichild(hpdev, hv_pcidev_ref_childlist);
+	put_pcichild(hpdev, hv_pcidev_ref_initial);
 	put_pcichild(hpdev, hv_pcidev_ref_pnp);
 	put_hvpcibus(hpdev->hbus);
 }
-- 
2.17.1