linux-kernel - [PATCH] vfio: pci: fix oops in case of vfio_msi_set_vector

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Date:	Fri, 29 Jan 2016 14:43:06 +0000
From:	Eric Auger <eric.auger@...aro.org>
To:	eric.auger@...com, eric.auger@...aro.org,
	alex.williamson@...hat.com, linux-arm-kernel@...ts.infradead.org,
	christoffer.dall@...aro.org
Cc:	patches@...aro.org, linux-kernel@...r.kernel.org
Subject: [PATCH] vfio: pci: fix oops in case of vfio_msi_set_vector_signal failure

In case vfio_msi_set_vector_signal fails we tear down everything.
In the tear down loop we compare int j against unsigned start. Given
the arithmetic conversion I think it is converted into an unsigned and
becomes 0xffffffff, leading to the loop being entered again and things
turn bad when accessing vdev->msix[vector].vector. So let's use int
parameters instead.

Signed-off-by: Eric Auger <eric.auger@...aro.org>
---
 drivers/vfio/pci/vfio_pci_intrs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 3b3ba15..510c48d 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -374,8 +374,8 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev,
 	return 0;
 }
 
-static int vfio_msi_set_block(struct vfio_pci_device *vdev, unsigned start,
-			      unsigned count, int32_t *fds, bool msix)
+static int vfio_msi_set_block(struct vfio_pci_device *vdev, int start,
+			      int count, int32_t *fds, bool msix)
 {
 	int i, j, ret = 0;
 
-- 
1.9.1