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/submittingpatches
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.
--
thomas
