From: Meenakshi Venkataraman <[email protected]>

The driver can potentially unmap pages that
have not been mapped yet. Fix this race
condition.

Cc: [email protected]
Reported-by: Emmanuel Grumbach <[email protected]>
Signed-off-by: Meenakshi Venkataraman <[email protected]>
Signed-off-by: Wey-Yi Guy <[email protected]>
---
this patch will be also available from wireless branch on
 git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi.git

 drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c 
b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
index aa7aea1..173275f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
@@ -310,7 +310,6 @@ static void iwlagn_rx_allocate(struct iwl_trans *trans, 
gfp_t priority)
                spin_unlock_irqrestore(&rxq->lock, flags);
 
                BUG_ON(rxb->page);
-               rxb->page = page;
                /* Get physical address of the RB */
                rxb->page_dma = dma_map_page(trans->dev, page, 0,
                                PAGE_SIZE << hw_params(trans).rx_page_order,
@@ -320,6 +319,9 @@ static void iwlagn_rx_allocate(struct iwl_trans *trans, 
gfp_t priority)
                /* and also 256 byte aligned! */
                BUG_ON(rxb->page_dma & DMA_BIT_MASK(8));
 
+               /* Page *must* be mapped before before updating the rxb. */
+               rxb->page = page;
+
                spin_lock_irqsave(&rxq->lock, flags);
 
                list_add_tail(&rxb->list, &rxq->rx_free);
-- 
1.7.0.4

--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to