>From Dale Farnsworth <[email protected]>
mv643xx_eth: Fix race condition in mv643xx_eth_free_tx_descs
This bug was found and isolated by Thibaut VARENE <[email protected]>
and Jarek Poplawski <[email protected]>. This patch is a modification of their
fixes. We acquire and release the lock for each descriptor that is freed
to minimize the time the lock is held.
---
drivers/net/mv643xx_eth.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index c41ae42..b3bf864 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -314,6 +314,13 @@ int mv643xx_eth_free_tx_descs(struct net
while (mp->tx_desc_count > 0) {
spin_lock_irqsave(&mp->lock, flags);
+
+ /* tx_desc_count might have changed before acquiring the lock */
+ if (mp->tx_desc_count <= 0) {
+ spin_unlock_irqrestore(&mp->lock, flags);
+ return released;
+ }
+
tx_index = mp->tx_used_desc_q;
desc = &mp->p_tx_desc_area[tx_index];
cmd_sts = desc->cmd_sts;
@@ -332,13 +339,13 @@ int mv643xx_eth_free_tx_descs(struct net
if (skb)
mp->tx_skb[tx_index] = NULL;
- spin_unlock_irqrestore(&mp->lock, flags);
-
if (cmd_sts & ETH_ERROR_SUMMARY) {
printk("%s: Error in TX\n", dev->name);
mp->stats.tx_errors++;
}
+ spin_unlock_irqrestore(&mp->lock, flags);
+
if (cmd_sts & ETH_TX_FIRST_DESC)
dma_unmap_single(NULL, addr, count, DMA_TO_DEVICE);
else
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
