This is a note to let you know that I've just added the patch titled mwifiex: remove redundant dma padding in AMSDU 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: mwifiex-remove-redundant-dma-padding-in-amsdu.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 5f0a221f59ad6b72202ef9c6e232086de8c336f2 Mon Sep 17 00:00:00 2001 From: Xinming Hu <huxm@xxxxxxxxxxx> Date: Wed, 11 Jan 2017 21:41:24 +0530 Subject: mwifiex: remove redundant dma padding in AMSDU From: Xinming Hu <huxm@xxxxxxxxxxx> commit 5f0a221f59ad6b72202ef9c6e232086de8c336f2 upstream. We already ensure 64 bytes alignment and add padding if required during skb_aggr allocation. Alignment and padding in mwifiex_11n_form_amsdu_txpd() is redundant. We may end up accessing more data than allocated size with this. This patch fixes following issue by removing redundant padding. [ 370.241338] skbuff: skb_over_panic: text:ffffffffc046946a len:3550 put:72 head:ffff880000110000 data:ffff8800001100e4 tail:0xec2 end:0xec0 dev:<NULL> [ 370.241374] ------------[ cut here ]------------ [ 370.241382] kernel BUG at net/core/skbuff.c:104! 370.244032] Call Trace: [ 370.244041] [<ffffffff8c3df5ec>] skb_put+0x44/0x45 [ 370.244055] [<ffffffffc046946a>] mwifiex_11n_aggregate_pkt+0x1e9/0xa50 [mwifiex] [ 370.244067] [<ffffffffc0467c16>] mwifiex_wmm_process_tx+0x44a/0x6b7 [mwifiex] [ 370.244074] [<ffffffffc0411eb8>] ? 0xffffffffc0411eb8 [ 370.244084] [<ffffffffc046116b>] mwifiex_main_process+0x476/0x5a5 [mwifiex] [ 370.244098] [<ffffffffc0461298>] mwifiex_main_process+0x5a3/0x5a5 [mwifiex] [ 370.244113] [<ffffffff8be7e9ff>] process_one_work+0x1a4/0x309 [ 370.244123] [<ffffffff8be7f4ca>] worker_thread+0x20c/0x2ee [ 370.244130] [<ffffffff8be7f2be>] ? rescuer_thread+0x383/0x383 [ 370.244136] [<ffffffff8be7f2be>] ? rescuer_thread+0x383/0x383 [ 370.244143] [<ffffffff8be83742>] kthread+0x11c/0x124 [ 370.244150] [<ffffffff8be83626>] ? kthread_parkme+0x24/0x24 [ 370.244157] [<ffffffff8c4da1ef>] ret_from_fork+0x3f/0x70 [ 370.244168] [<ffffffff8be83626>] ? kthread_parkme+0x24/0x24 Fixes: 84b313b35f8158d ("mwifiex: make tx packet 64 byte DMA aligned") Signed-off-by: Xinming Hu <huxm@xxxxxxxxxxx> Signed-off-by: Amitkumar Karwar <akarwar@xxxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/mwifiex/11n_aggr.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) --- a/drivers/net/wireless/mwifiex/11n_aggr.c +++ b/drivers/net/wireless/mwifiex/11n_aggr.c @@ -101,13 +101,6 @@ mwifiex_11n_form_amsdu_txpd(struct mwifi { struct txpd *local_tx_pd; struct mwifiex_txinfo *tx_info = MWIFIEX_SKB_TXCB(skb); - unsigned int pad; - int headroom = (priv->adapter->iface_type == - MWIFIEX_USB) ? 0 : INTF_HEADER_LEN; - - pad = ((void *)skb->data - sizeof(*local_tx_pd) - - headroom - NULL) & (MWIFIEX_DMA_ALIGN_SZ - 1); - skb_push(skb, pad); skb_push(skb, sizeof(*local_tx_pd)); @@ -121,12 +114,10 @@ mwifiex_11n_form_amsdu_txpd(struct mwifi local_tx_pd->bss_num = priv->bss_num; local_tx_pd->bss_type = priv->bss_type; /* Always zero as the data is followed by struct txpd */ - local_tx_pd->tx_pkt_offset = cpu_to_le16(sizeof(struct txpd) + - pad); + local_tx_pd->tx_pkt_offset = cpu_to_le16(sizeof(struct txpd)); local_tx_pd->tx_pkt_type = cpu_to_le16(PKT_TYPE_AMSDU); local_tx_pd->tx_pkt_length = cpu_to_le16(skb->len - - sizeof(*local_tx_pd) - - pad); + sizeof(*local_tx_pd)); if (tx_info->flags & MWIFIEX_BUF_FLAG_TDLS_PKT) local_tx_pd->flags |= MWIFIEX_TXPD_FLAGS_TDLS_PACKET; @@ -190,7 +181,11 @@ mwifiex_11n_aggregate_pkt(struct mwifiex ra_list_flags); return -1; } - skb_reserve(skb_aggr, MWIFIEX_MIN_DATA_HEADER_LEN); + + /* skb_aggr->data already 64 byte align, just reserve bus interface + * header and txpd. + */ + skb_reserve(skb_aggr, headroom + sizeof(struct txpd)); tx_info_aggr = MWIFIEX_SKB_TXCB(skb_aggr); memset(tx_info_aggr, 0, sizeof(*tx_info_aggr)); Patches currently in stable-queue which might be from huxm@xxxxxxxxxxx are queue-4.4/mwifiex-remove-redundant-dma-padding-in-amsdu.patch