Hi Felix, I need to submit v2 patch. Please drop this one. Thanks, Deren On Thu, 2022-03-03 at 11:28 +0800, Deren Wu wrote: > From: Deren Wu <deren.wu@xxxxxxxxxxxx> > > mt7921s driver may receive frames with fragment buffers. If there is > a > CTS packet received in monitor mode, the payload is 10 bytes only and > need 6 bytes header padding after RXD buffer. However, only RXD in > the > first linear buffer, if we pull buffer size RXD-size+6 bytes with > skb_pull(), that would trigger "BUG_ON(skb->len < skb->data_len)" in > __skb_pull(). > > To avoid the nonlinear buffer issue, enlarge the RXD size from 128 to > 136 to make sure all MCU operation in linear buffer. > > 136 = 128 + 8 > 128 : RXD size > 8 : max header padding length > > [ 52.007562] kernel BUG at include/linux/skbuff.h:2313! > [ 52.007578] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP > [ 52.007987] pc : skb_pull+0x48/0x4c > [ 52.008015] lr : mt7921_queue_rx_skb+0x494/0x890 [mt7921_common] > [ 52.008361] Call trace: > [ 52.008377] skb_pull+0x48/0x4c > [ 52.008400] mt76s_net_worker+0x134/0x1b0 [mt76_sdio > 35339a92c6eb7d4bbcc806a1d22f56365565135c] > [ 52.008431] __mt76_worker_fn+0xe8/0x170 [mt76 > ef716597d11a77150bc07e3fdd68eeb0f9b56917] > [ 52.008449] kthread+0x148/0x3ac > [ 52.008466] ret_from_fork+0x10/0x30 > > Co-developed-by: Sean Wang <sean.wang@xxxxxxxxxxxx> > Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx> > Signed-off-by: Deren Wu <deren.wu@xxxxxxxxxxxx> > --- > drivers/net/wireless/mediatek/mt76/mt76.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h > b/drivers/net/wireless/mediatek/mt76/mt76.h > index 5e10fe156926..4f4ce3b3df54 100644 > --- a/drivers/net/wireless/mediatek/mt76/mt76.h > +++ b/drivers/net/wireless/mediatek/mt76/mt76.h > @@ -19,7 +19,8 @@ > > #define MT_MCU_RING_SIZE 32 > #define MT_RX_BUF_SIZE 2048 > -#define MT_SKB_HEAD_LEN 128 > +/* 136 = 128+8. 128: RXD, 8:max header padding*/ > +#define MT_SKB_HEAD_LEN 136 > > #define MT_MAX_NON_AQL_PKT 16 > #define MT_TXQ_FREE_THR 32
