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From: Dexuan Cui <decui@microsoft.com>
To: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	KY Srinivasan <kys@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Sasha Levin <Alexander.Levin@microsoft.com>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"olaf@aepfle.de" <olaf@aepfle.de>,
	"apw@canonical.com" <apw@canonical.com>,
	"jasowang@redhat.com" <jasowang@redhat.com>,
	vkuznets <vkuznets@redhat.com>,
	"marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>,
	Michael Kelley <mikelley@microsoft.com>
Cc: "Lili Deng (Wicresoft North America Ltd)" <v-lide@microsoft.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"driverdev-devel@linuxdriverproject.org" 
	<driverdev-devel@linuxdriverproject.org>
Subject: [PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work()
Date: Fri, 21 Jun 2019 19:02:26 +0000	[thread overview]
Message-ID: <PU1P153MB01691036654142C7972F3ACDBFE70@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM> (raw)


The commit 05f151a73ec2 itself is correct, but it exposes this
use-after-free bug, which is caught by some memory debug options.

Add the Fixes tag to indicate the dependency.

Fixes: 05f151a73ec2 ("PCI: hv: Fix a memory leak in hv_eject_device_work()")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
---
Sorry for not spotting the bug when sending 05f151a73ec2. 

Now I have enabled the mm debug options to help catch such mistakes in future.

 drivers/pci/controller/pci-hyperv.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 808a182830e5..42ace1a690f9 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1880,6 +1880,7 @@ 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;
@@ -1890,6 +1891,7 @@ 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);
 
@@ -1929,7 +1931,9 @@ 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);
 }
 
 /**
-- 
2.17.1


             reply	other threads:[~2019-06-21 19:02 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-21 19:02 Dexuan Cui [this message]
2019-06-21 23:24 ` [PATCH] PCI: hv: Fix a use-after-free bug in hv_eject_device_work() Michael Kelley
2019-06-21 23:31   ` Dexuan Cui

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