From d5d0689aefc59c6a5352ca25d7e6d47d03f543ce Mon Sep 17 00:00:00 2001 From: Sara Sharon Date: Thu, 9 Jun 2016 17:19:35 +0300 Subject: [PATCH] iwlwifi: pcie: fix access to scratch buffer This fixes a pretty ancient bug that hasn't manifested itself until now. The scratchbuf for command queue is allocated only for 32 slots but is accessed with the queue write pointer - which can be up to 256. Since the scratch buf size was 16 and there are up to 256 TFDs we never passed a page boundary when accessing the scratch buffer, but when attempting to increase the size of the scratch buffer a panic was quick to follow when trying to access the address resulted in a page boundary. Signed-off-by: Sara Sharon Fixes: 38c0f334b359 ("iwlwifi: use coherent DMA memory for command header") Signed-off-by: Luca Coelho --- drivers/net/wireless/intel/iwlwifi/pcie/tx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c index 8901d49aebd5..9b5858bc8ee2 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c @@ -1604,9 +1604,9 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans, /* start the TFD with the scratchbuf */ scratch_size = min_t(int, copy_size, IWL_HCMD_SCRATCHBUF_SIZE); - memcpy(&txq->scratchbufs[q->write_ptr], &out_cmd->hdr, scratch_size); + memcpy(&txq->scratchbufs[idx], &out_cmd->hdr, scratch_size); iwl_pcie_txq_build_tfd(trans, txq, - iwl_pcie_get_scratchbuf_dma(txq, q->write_ptr), + iwl_pcie_get_scratchbuf_dma(txq, idx), scratch_size, true); /* map first command fragment, if any remains */ -- 2.20.1