FAILED: patch "[PATCH] PCI: hv: Fix a memory leak in hv_eject_device_work()" failed to apply to 4.9-stable tree

PATCH Applied [email protected] 3 participants 3 messages May 15, 2019 – May 17, 2019

Subsystems (4)

Stable branch PCI PCI native host bridge and endpoint drivers Hyper-V/Azure core and drivers

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lore

[email protected]

author maintainer

2019-05-15 08:34 UTC #0 lore raw

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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 05f151a73ec2b23ffbff706e5203e729a995cdc2 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
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 <[email protected]>

[[email protected]: commit log rework]

Signed-off-by Lorenzo Pieralisi <[email protected]>

Reviewed-by Stephen Hemminger <[email protected]>

Reviewed-by Michael Kelley <[email protected]>

Cc [email protected]

drivers/pci/controller/pci-hyperv.c +3 -0

index 95441a35eceb..30f16b882746 100644
@@ -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);

Dexuan Cui

maintainer

2019-05-15 23:14 UTC #1 lore raw

Quoted 67 lines

From: [email protected] <[email protected]>
Sent: Wednesday, May 15, 2019 1:35 AM
To: Dexuan Cui <[email protected]>; [email protected]; Michael Kelley <[email protected]>; [email protected]
Cc: [email protected]
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 <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 05f151a73ec2b23ffbff706e5203e729a995cdc2 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
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 <[email protected]>
[[email protected]: commit log rework]
Signed-off-by Lorenzo Pieralisi <[email protected]>
Reviewed-by Stephen Hemminger <[email protected]>
Reviewed-by Michael Kelley <[email protected]>
Cc [email protected]
drivers/pci/controller/pci-hyperv.c +3 -0
index 95441a35eceb..30f16b882746 100644
@@ -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);

Quoted 1 line

put_hvpcibus(hpdev->hbus);

Hi,
I backported the patch for linux-4.9.y. Please use the attached patch.

Thanks,
-- Dexuan

From 151f2bc2afcc71ddba7b1978cb736cf13c4eeff0 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
Date: Wed, 15 May 2019 15:42:07 -0700
Subject: [PATCH][For v4.9.176] PCI: hv: Fix a memory leak in hv_eject_device_work()

This patch is backported for v4.9.176 from the mainline
commit 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()")

Signed-off-by Dexuan Cui <[email protected]>

---
 drivers/pci/host/pci-hyperv.c | 1 +
 1 file changed, 1 insertion(+)

drivers/pci/host/pci-hyperv.c +1 -0

index b4d8ccfd9f7c..200b41576526 100644
@@ -1620,6 +1620,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
 
 	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);
 }

Signature · 1 line

2.17.1

Sasha Levin

maintainer Applied

2019-05-17 00:43 UTC #2 lore raw

Quoted 72 lines · Dexuan Cui

Quoted 67 lines
From: [email protected] <[email protected]>
Sent: Wednesday, May 15, 2019 1:35 AM
To: Dexuan Cui <[email protected]>; [email protected]; Michael Kelley <[email protected]>; [email protected]
Cc: [email protected]
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 <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 05f151a73ec2b23ffbff706e5203e729a995cdc2 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
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 <[email protected]>
[[email protected]: commit log rework]
Signed-off-by Lorenzo Pieralisi <[email protected]>
Reviewed-by Stephen Hemminger <[email protected]>
Reviewed-by Michael Kelley <[email protected]>
Cc [email protected]
drivers/pci/controller/pci-hyperv.c +3 -0
index 95441a35eceb..30f16b882746 100644
@@ -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);
Quoted 1 line
put_hvpcibus(hpdev->hbus);
Hi,
I backported the patch for linux-4.9.y. Please use the attached patch.

Quoted 2 lines

Thanks,
-- Dexuan

Queued for 4.9, thanks.

--
Thanks,
Sasha