The refcount_t API will WARN on underflow and overflow of a reference
counter, and avoid use-after-free risks. Increase refcount_t from 0 to 1 is
regarded as there is a risk about use-after-free. So it should be set to 1
directly during initialization.
Signed-off-by: Weihang Li <liweihang@xxxxxxxxxx>
---
drivers/infiniband/core/iwpm_util.c | 12 ++++++++----
drivers/infiniband/core/iwpm_util.h | 2 +-
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/infiniband/core/iwpm_util.c b/drivers/infiniband/core/iwpm_util.c
index f80e555..b8f40e6 100644
--- a/drivers/infiniband/core/iwpm_util.c
+++ b/drivers/infiniband/core/iwpm_util.c
@@ -61,7 +61,7 @@ int iwpm_init(u8 nl_client)
{
int ret = 0;
mutex_lock(&iwpm_admin_lock);
- if (atomic_read(&iwpm_admin.refcount) == 0) {
+ if (!refcount_read(&iwpm_admin.refcount)) {
iwpm_hash_bucket = kcalloc(IWPM_MAPINFO_HASH_SIZE,
sizeof(struct hlist_head),
GFP_KERNEL);
@@ -77,8 +77,12 @@ int iwpm_init(u8 nl_client)
ret = -ENOMEM;
goto init_exit;
}
+
+ refcount_set(&iwpm_admin.refcount, 1);
+ } else {
+ refcount_inc(&iwpm_admin.refcount);
}
- atomic_inc(&iwpm_admin.refcount);
+
init_exit:
mutex_unlock(&iwpm_admin_lock);
if (!ret) {
@@ -105,12 +109,12 @@ int iwpm_exit(u8 nl_client)
if (!iwpm_valid_client(nl_client))
return -EINVAL;
mutex_lock(&iwpm_admin_lock);
- if (atomic_read(&iwpm_admin.refcount) == 0) {
+ if (!refcount_read(&iwpm_admin.refcount)) {
mutex_unlock(&iwpm_admin_lock);
pr_err("%s Incorrect usage - negative refcount\n", __func__);
return -EINVAL;
}
- if (atomic_dec_and_test(&iwpm_admin.refcount)) {
+ if (refcount_dec_and_test(&iwpm_admin.refcount)) {
free_hash_bucket();
free_reminfo_bucket();
pr_debug("%s: Resources are destroyed\n", __func__);
diff --git a/drivers/infiniband/core/iwpm_util.h b/drivers/infiniband/core/iwpm_util.h
index eeb8e60..5002ac6 100644
--- a/drivers/infiniband/core/iwpm_util.h
+++ b/drivers/infiniband/core/iwpm_util.h
@@ -90,7 +90,7 @@ struct iwpm_remote_info {
};
struct iwpm_admin_data {
- atomic_t refcount;
+ refcount_t refcount;
atomic_t nlmsg_seq;
int client_list[RDMA_NL_NUM_CLIENTS];
u32 reg_list[RDMA_NL_NUM_CLIENTS];
--
2.7.4
