This is a note to let you know that I've just added the patch titled net: mvpp2: release reference to txq_cpu[] entry after unmapping to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-mvpp2-release-reference-to-txq_cpu-entry-after-unmapping.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Oct 19 15:15:46 CEST 2017 From: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> Date: Tue, 21 Feb 2017 11:28:05 +0100 Subject: net: mvpp2: release reference to txq_cpu[] entry after unmapping From: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> [ Upstream commit 36fb7435b6ac4d288a2d4deea8934f9456ab46b6 ] The mvpp2_txq_bufs_free() function is called upon TX completion to DMA unmap TX buffers, and free the corresponding SKBs. It gets the references to the SKB to free and the DMA buffer to unmap from a per-CPU txq_pcpu data structure. However, the code currently increments the pointer to the next entry before doing the DMA unmap and freeing the SKB. It does not cause any visible problem because for a given SKB the TX completion is guaranteed to take place on the CPU where the TX was started. However, it is much more logical to increment the pointer to the next entry once the current entry has been completely unmapped/released. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/marvell/mvpp2.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/drivers/net/ethernet/marvell/mvpp2.c +++ b/drivers/net/ethernet/marvell/mvpp2.c @@ -4415,13 +4415,12 @@ static void mvpp2_txq_bufs_free(struct m struct mvpp2_txq_pcpu_buf *tx_buf = txq_pcpu->buffs + txq_pcpu->txq_get_index; - mvpp2_txq_inc_get(txq_pcpu); - dma_unmap_single(port->dev->dev.parent, tx_buf->phys, tx_buf->size, DMA_TO_DEVICE); - if (!tx_buf->skb) - continue; - dev_kfree_skb_any(tx_buf->skb); + if (tx_buf->skb) + dev_kfree_skb_any(tx_buf->skb); + + mvpp2_txq_inc_get(txq_pcpu); } } Patches currently in stable-queue which might be from thomas.petazzoni@xxxxxxxxxxxxxxxxxx are queue-4.4/net-mvpp2-release-reference-to-txq_cpu-entry-after-unmapping.patch