[PATCH 5.7 070/244] xen/xenbus: Fix a double free in xenbus_map_ring_pv()

From: Greg Kroah-Hartman
Date: Mon Jul 20 2020 - 12:08:40 EST


From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

[ Upstream commit ba8c423488974f02b538e9dc1730f0334f9b85aa ]

When there is an error the caller frees "info->node" so the free here
will result in a double free. We should just delete first kfree().

Fixes: 3848e4e0a32a ("xen/xenbus: avoid large structs and arrays on the stack")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200710113610.GA92345@mwanda
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/xen/xenbus/xenbus_client.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 4f168b46fbca5..786fbb7d8be06 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -693,10 +693,8 @@ static int xenbus_map_ring_pv(struct xenbus_device *dev,
bool leaked;

area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, info->ptes);
- if (!area) {
- kfree(node);
+ if (!area)
return -ENOMEM;
- }

for (i = 0; i < nr_grefs; i++)
info->phys_addrs[i] =
--
2.25.1