commit 4437ba7ee7de7e71d11deb91c87a370e4ffd2601 upstream.

Our Transmit Frame Descriptor (TFD) is a DMA descriptor that includes several pointers to be able to transmit a packet which is not physically contiguous.

Depending on the hardware being use, we can have 20 or 25 pointers in a single TFD. In both cases, it is more than enough and it is quite hard to hit this limit. It has been reported that when using specific applications (Ktorrent), we can actually use all the pointers and then a long standing bug showed up.

When we free the TFD, we check its number of valid pointers and make sure it doesn't exceed the number of pointers the hardware support. This check had an off by one bug: it is perfectly valid to free the 20 pointers if the TFD has 20 pointers.

Fix that.

https://bugzilla.kernel.org/show_bug.cgi?id=197981

Signed-off-by: Emmanuel Grumbach emmanuel.grumbach@intel.com Signed-off-by: Luca Coelho luciano.coelho@intel.com --- drivers/net/wireless/intel/iwlwifi/pcie/tx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c index e1bfc95..2c98784 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c @@ -416,7 +416,7 @@ static void iwl_pcie_tfd_unmap(struct iwl_trans *trans, /* Sanity check on number of chunks */ num_tbs = iwl_pcie_tfd_get_num_tbs(trans, tfd);

- if (num_tbs >= trans_pcie->max_tbs) { + if (num_tbs > trans_pcie->max_tbs) { IWL_ERR(trans, "Too many chunks: %i\n", num_tbs); /* @todo issue fatal error, it is quite serious situation */ return;