提交 3a24934f 编写于 作者: I Inaky Perez-Gonzalez

wimax/i2400m: fix bad race condition check in RX path

The i2400m->rx_roq data structure is protected against race conditions
with a reference count (i2400m->rx_roq_refcount); the pointer can be
read-referenced under the i2400m->rx_lock spinlock.

The code in i2400m_rx_edata() wasn't properly following access
protocol, performing an invalid check on i2400m->rx_roq (which is
cleared to NULL when the refcount drops to zero). As such, it was
missing to detect when the data structure is no longer valid and
oopsing with a NULL pointer dereference.

This commit fixes said check by verifying, under the rx_lock spinlock,
that i2400m->rx_roq is non-NULL and then increasing the reference
count before dropping the spinlock.
Signed-off-by: NInaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
上级 0fb0a4f0
......@@ -1033,12 +1033,12 @@ void i2400m_rx_edata(struct i2400m *i2400m, struct sk_buff *skb_rx,
ro_sn = (reorder >> I2400M_RO_SN_SHIFT) & I2400M_RO_SN;
spin_lock_irqsave(&i2400m->rx_lock, flags);
roq = &i2400m->rx_roq[ro_cin];
if (roq == NULL) {
if (i2400m->rx_roq == NULL) {
kfree_skb(skb); /* rx_roq is already destroyed */
spin_unlock_irqrestore(&i2400m->rx_lock, flags);
goto error;
}
roq = &i2400m->rx_roq[ro_cin];
kref_get(&i2400m->rx_roq_refcount);
spin_unlock_irqrestore(&i2400m->rx_lock, flags);
......
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