From: Inaky Perez-Gonzalez <[email protected]> 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 As such, it was missing to detect when the data structure is no longer valid and oopsing with a NULL pointer dereference.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: Inaky Perez-Gonzalez <[email protected]> --- drivers/net/wimax/i2400m/rx.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wimax/i2400m/rx.c b/drivers/net/wimax/i2400m/rx.c index c835ae8..6cd12d6 100644 --- a/drivers/net/wimax/i2400m/rx.c +++ b/drivers/net/wimax/i2400m/rx.c @@ -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); -- 1.6.6.1 _______________________________________________ wimax mailing list [email protected] http://lists.linuxwimax.org/listinfo/wimax
