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PCI: hv: Convert hv_pci_dev.refs from atomic_t to refcount_t

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refcount_t type and corresponding API should be used instead of atomic_t
when the variable is used as a reference counter.  This allows to avoid
accidental refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
This commit is contained in:
Elena Reshetova 2017-04-18 09:02:48 -05:00 committed by Bjorn Helgaas
parent 59c58ceeea
commit 24196f0c7d
1 changed files with 5 additions and 4 deletions
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9
drivers/pci/host/pci-hyperv.c
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@ -56,6 +56,7 @@
#include <asm/apic.h>
#include <linux/msi.h>
#include <linux/hyperv.h>
#include <linux/refcount.h>
#include <asm/mshyperv.h>
/*
@ -423,7 +424,7 @@ enum hv_pcidev_ref_reason {
struct hv_pci_dev {
/* List protected by pci_rescan_remove_lock */
struct list_head list_entry;
atomic_t refs;
refcount_t refs;
enum hv_pcichild_state state;
struct pci_function_description desc;
bool reported_missing;
@ -1262,13 +1263,13 @@ static void q_resource_requirements(void *context, struct pci_response *resp,
static void get_pcichild(struct hv_pci_dev *hpdev,
enum hv_pcidev_ref_reason reason)
{
atomic_inc(&hpdev->refs);
refcount_inc(&hpdev->refs);
}
static void put_pcichild(struct hv_pci_dev *hpdev,
enum hv_pcidev_ref_reason reason)
{
if (atomic_dec_and_test(&hpdev->refs))
if (refcount_dec_and_test(&hpdev->refs))
kfree(hpdev);
}
@ -1322,7 +1323,7 @@ static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus,
wait_for_completion(&comp_pkt.host_event);
hpdev->desc = *desc;
get_pcichild(hpdev, hv_pcidev_ref_initial);
refcount_set(&hpdev->refs, 1);
get_pcichild(hpdev, hv_pcidev_ref_childlist);
spin_lock_irqsave(&hbus->device_list_lock, flags);