> On 2020-06-25 13:18, Nick Owens wrote: > > hello :) > > Hi Nick :) > > > this change fixes a reliable crash on my thinkpad A485. > > > > please note i have no prior experience doing kernel development or > > sending patches, and i'm not sure if this is a correct approach. > > You probably want to submit patches with git-send-email. See > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatch > es > > > From aa589182d30a0f99e1b3201ed4f3830e8af71dac Mon Sep 17 00:00:00 > 2001 > > From: Nick Owens <mischief@xxxxxxxxxxxx> > > Date: Thu, 25 Jun 2020 12:55:41 -0700 > > Subject: [PATCH] rtw88: fix skb_under_panic in tx path > > > > fixes the following panic on my thinkpad A485 > > > > Oops#1 Part3 > > <0>[ 3743.881656] skbuff: skb_under_panic: text:000000005f69fd98 > > len:208 put:48 head:000000009e2719e8 data:00000000bd3795e0 tail:0xc2 > > end:0x2c0 dev:wlp2s0 > > skb->head and skb->data here are really far (0.5GB) apart. Maybe > skb->data actually got corrupted earlier? > > > diff --git a/drivers/net/wireless/realtek/rtw88/pci.c > > b/drivers/net/wireless/realtek/rtw88/pci.c > > index d735f3127fe8..21b3b268cb25 100644 > > --- a/drivers/net/wireless/realtek/rtw88/pci.c > > +++ b/drivers/net/wireless/realtek/rtw88/pci.c > > @@ -741,6 +741,12 @@ static int rtw_pci_tx_write_data(struct rtw_dev > > *rtwdev, > > else if (!avail_desc(ring->r.wp, ring->r.rp, ring->r.len)) > > return -ENOSPC; > > > > + if (skb_headroom(skb) < chip->tx_pkt_desc_sz && > > + pskb_expand_head(skb, chip->tx_pkt_desc_sz - skb_headroom(skb), > > 0, GFP_ATOMIC)) { > > + dev_err(rtwdev->dev, "no headroom available"); > > + return -ENOMEM; > > + } > > + > > If it is a headroom issue, you can actually express the needed headroom > needed by the driver in hw->extra_tx_headroom during init and avoid the > pskb_expand_head() here. > Looks like a headroom issue, but the driver already assigned headroom. max_tx_headroom = rtwdev->chip->tx_pkt_desc_sz; hw->extra_tx_headroom = max_tx_headroom; Then I am not sure why this happens. Nick, can you help to dump_stack() so we can see where is the skb from? Yen-Hsuan
