FAILED: patch "[PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()" failed to apply to 4.9-stable tree

PATCH [email protected] 2 participants 3 messages Jul 23, 2019 – Jul 24, 2019

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

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[email protected]

author maintainer

2019-07-23 11:59 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 4df591b20b80cb77920953812d894db259d85bd7 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
Date: Fri, 21 Jun 2019 23:45:23 +0000
Subject: [PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()

Fix a use-after-free in hv_eject_device_work().

Fixes 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()")

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

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

Reviewed-by Michael Kelley <[email protected]>

Cc [email protected]

drivers/pci/controller/pci-hyperv.c +9 -6

index 82acd6155adf..40b625458afa 100644
@@ -1875,6 +1875,7 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
 static void hv_eject_device_work(struct work_struct *work)
 {
 	struct pci_eject_response *ejct_pkt;
+	struct hv_pcibus_device *hbus;
 	struct hv_pci_dev *hpdev;
 	struct pci_dev *pdev;
 	unsigned long flags;

@@ -1885,6 +1886,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	} ctxt;
 
 	hpdev = container_of(work, struct hv_pci_dev, wrk);
+	hbus = hpdev->hbus;
 
 	WARN_ON(hpdev->state != hv_pcichild_ejecting);

@@ -1895,8 +1897,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	 * because hbus->pci_bus may not exist yet.
 	 */
 	wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
-	pdev = pci_get_domain_bus_and_slot(hpdev->hbus->sysdata.domain, 0,
-					   wslot);
+	pdev = pci_get_domain_bus_and_slot(hbus->sysdata.domain, 0, wslot);
 	if (pdev) {
 		pci_lock_rescan_remove();
 		pci_stop_and_remove_bus_device(pdev);

@@ -1904,9 +1905,9 @@ static void hv_eject_device_work(struct work_struct *work)
 		pci_unlock_rescan_remove();
 	}
 
-	spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags);
+	spin_lock_irqsave(&hbus->device_list_lock, flags);
 	list_del(&hpdev->list_entry);
-	spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
+	spin_unlock_irqrestore(&hbus->device_list_lock, flags);
 
 	if (hpdev->pci_slot)
 		pci_destroy_slot(hpdev->pci_slot);

@@ -1915,7 +1916,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
 	ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
 	ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
-	vmbus_sendpacket(hpdev->hbus->hdev->channel, ejct_pkt,
+	vmbus_sendpacket(hbus->hdev->channel, ejct_pkt,
 			 sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
 			 VM_PKT_DATA_INBAND, 0);

@@ -1924,7 +1925,9 @@ static void hv_eject_device_work(struct work_struct *work)
 	/* For the two refs got in new_pcichild_device() */
 	put_pcichild(hpdev);
 	put_pcichild(hpdev);
-	put_hvpcibus(hpdev->hbus);
+	/* hpdev has been freed. Do not use it any more. */
+
+	put_hvpcibus(hbus);
 }
 
 /**

Dexuan Cui

maintainer Reviewed-by Jake Oshins Acked-by K. Y. Srinivasan Reviewed-by Michael Kelley

2019-07-24 01:00 UTC #1 lore raw

Quoted 18 lines

From: [email protected] <[email protected]>
Sent: Tuesday, July 23, 2019 4:59 AM
To: Dexuan Cui <[email protected]>; [email protected]; Michael Kelley <[email protected]>
Cc: [email protected]
Subject: FAILED: patch "[PATCH] PCI: hv: Fix a use-after-free bug 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

Quoted 7 lines

------------------ original commit in Linus's tree ------------------
From 4df591b20b80cb77920953812d894db259d85bd7 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
Date: Fri, 21 Jun 2019 23:45:23 +0000
Subject: [PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()

Hi,
To apply this patch to v4.9.186, we need to cherry-pick another patch first:
e74d2ebdda33 ("PCI: hv: Delete the device earlier from hbus->children for hot-remove")

Then I backported this commit (4df591b20)

Please see the two attachments for the two patches. They can be cleanly applied to v4.9.186.

Thanks,
-- Dexuan

From 70913034cdcf061020573d64d4890c3781c63b6b Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
Date: Thu, 10 Nov 2016 07:19:52 +0000
Subject: [PATCH for-4.9.186 1/2] PCI: hv: Delete the device earlier from
hbus->children for hot-remove
Reply-To: [email protected]

[ Upstream commit e74d2ebdda33b3bdd1826b5b92e9aa45bdf92bb3 ]

After we send a PCI_EJECTION_COMPLETE message to the host, the host will immediately send us a PCI_BUS_RELATIONS message with relations->device_count == 0, so pci_devices_present_work(), running on another thread, can find the being-ejected device, mark the hpdev->reported_missing to true, and run list_move_tail()/list_del() for the device -- this races hv_eject_device_work() -> list_del().

Move the list_del() in hv_eject_device_work() to an earlier place, i.e., before we send PCI_EJECTION_COMPLETE, so later the pci_devices_present_work() can't see the device.

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

Signed-off-by Bjorn Helgaas <[email protected]>

Reviewed-by Jake Oshins <[email protected]>

Acked-by K. Y. Srinivasan <[email protected]>

CC Haiyang Zhang <[email protected]>

CC Vitaly Kuznetsov <[email protected]>

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

---
 drivers/pci/host/pci-hyperv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

drivers/pci/host/pci-hyperv.c +4 -4

index 200b415..499461c 100644
@@ -1607,6 +1607,10 @@ static void hv_eject_device_work(struct work_struct *work)
 		pci_unlock_rescan_remove();
 	}
 
+	spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags);
+	list_del(&hpdev->list_entry);
+	spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
+
 	memset(&ctxt, 0, sizeof(ctxt));
 	ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
 	ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;

@@ -1615,10 +1619,6 @@ static void hv_eject_device_work(struct work_struct *work)
 			 sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
 			 VM_PKT_DATA_INBAND, 0);
 
-	spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags);
-	list_del(&hpdev->list_entry);
-	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);

Signature · 1 line

1.8.3.1

From ec241858c53dd7fdc98a8f4ee4719bf64e0677f8 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
Date: Tue, 23 Jul 2019 17:30:41 -0700
Subject: [PATCH for-4.9.186 2/2] PCI: hv: Fix a use-after-free bug in
hv_eject_device_work()
Reply-To: [email protected]

[ Upstream commit 4df591b20b80cb77920953812d894db259d85bd7 ]

Fix a use-after-free in hv_eject_device_work().

Fixes 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()")

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

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

Reviewed-by Michael Kelley <[email protected]>

Cc [email protected]

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

---
 drivers/pci/host/pci-hyperv.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

drivers/pci/host/pci-hyperv.c +9 -6

index 499461c..a597619 100644
@@ -1575,6 +1575,7 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
 static void hv_eject_device_work(struct work_struct *work)
 {
 	struct pci_eject_response *ejct_pkt;
+	struct hv_pcibus_device *hbus;
 	struct hv_pci_dev *hpdev;
 	struct pci_dev *pdev;
 	unsigned long flags;

@@ -1585,6 +1586,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	} ctxt;
 
 	hpdev = container_of(work, struct hv_pci_dev, wrk);
+	hbus = hpdev->hbus;
 
 	if (hpdev->state != hv_pcichild_ejecting) {
 		put_pcichild(hpdev, hv_pcidev_ref_pnp);

@@ -1598,8 +1600,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	 * because hbus->pci_bus may not exist yet.
 	 */
 	wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
-	pdev = pci_get_domain_bus_and_slot(hpdev->hbus->sysdata.domain, 0,
-					   wslot);
+	pdev = pci_get_domain_bus_and_slot(hbus->sysdata.domain, 0, wslot);
 	if (pdev) {
 		pci_lock_rescan_remove();
 		pci_stop_and_remove_bus_device(pdev);

@@ -1607,22 +1608,24 @@ static void hv_eject_device_work(struct work_struct *work)
 		pci_unlock_rescan_remove();
 	}
 
-	spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags);
+	spin_lock_irqsave(&hbus->device_list_lock, flags);
 	list_del(&hpdev->list_entry);
-	spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
+	spin_unlock_irqrestore(&hbus->device_list_lock, flags);
 
 	memset(&ctxt, 0, sizeof(ctxt));
 	ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
 	ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
 	ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
-	vmbus_sendpacket(hpdev->hbus->hdev->channel, ejct_pkt,
+	vmbus_sendpacket(hbus->hdev->channel, ejct_pkt,
 			 sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
 			 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);
+
+	/* hpdev has been freed. Do not use it any more. */
+	put_hvpcibus(hbus);
 }
 
 /**

Signature · 1 line

1.8.3.1

[email protected]

author maintainer

2019-07-24 12:02 UTC #2 lore raw

Quoted 26 lines · Dexuan Cui

Quoted 18 lines
From: [email protected] <[email protected]>
Sent: Tuesday, July 23, 2019 4:59 AM
To: Dexuan Cui <[email protected]>; [email protected]; Michael Kelley <[email protected]>
Cc: [email protected]
Subject: FAILED: patch "[PATCH] PCI: hv: Fix a use-after-free bug 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
Quoted 7 lines
------------------ original commit in Linus's tree ------------------
From 4df591b20b80cb77920953812d894db259d85bd7 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <[email protected]>
Date: Fri, 21 Jun 2019 23:45:23 +0000
Subject: [PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()

Quoted 8 lines

Hi,
To apply this patch to v4.9.186, we need to cherry-pick another patch first:
e74d2ebdda33 ("PCI: hv: Delete the device earlier from hbus->children for hot-remove")
Then I backported this commit (4df591b20)
Please see the two attachments for the two patches. They can be cleanly applied to v4.9.186.

Now queued up, thanks.

greg k-h