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| author | Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> | 2010-05-20 12:27:58 -0700 |
|---|---|---|
| committer | Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> | 2010-05-20 12:27:58 -0700 |
| commit | 3a24934f065d23145f1c9c70da9f630c7a37795f (patch) | |
| tree | 0fac89df5f2749e21a45d2c07cf99d16e05ef2fc /drivers/net/wimax/i2400m | |
| parent | 0fb0a4f00aaf5de9f328273d7a46e3aa27dab496 (diff) | |
| download | lwn-3a24934f065d23145f1c9c70da9f630c7a37795f.tar.gz lwn-3a24934f065d23145f1c9c70da9f630c7a37795f.zip | |
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missing to detect when the data structure is no longer valid and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: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Diffstat (limited to 'drivers/net/wimax/i2400m')
| -rw-r--r-- | 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 c835ae8b89ce..6cd12d64fc7a 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); |