This is a note to let you know that I've just added the patch titled
p54: avoid accessing the data mapped to streaming DMA
to the 5.9-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:
p54-avoid-accessing-the-data-mapped-to-streaming-dma.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 478762855b5ae9f68fa6ead1edf7abada70fcd5f Mon Sep 17 00:00:00 2001
From: Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx>
Date: Sun, 2 Aug 2020 21:29:49 +0800
Subject: p54: avoid accessing the data mapped to streaming DMA
From: Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx>
commit 478762855b5ae9f68fa6ead1edf7abada70fcd5f upstream.
In p54p_tx(), skb->data is mapped to streaming DMA on line 337:
mapping = pci_map_single(..., skb->data, ...);
Then skb->data is accessed on line 349:
desc->device_addr = ((struct p54_hdr *)skb->data)->req_id;
This access may cause data inconsistency between CPU cache and hardware.
To fix this problem, ((struct p54_hdr *)skb->data)->req_id is stored in
a local variable before DMA mapping, and then the driver accesses this
local variable instead of skb->data.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx>
Acked-by: Christian Lamparter <chunkeey@xxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200802132949.26788-1-baijiaju@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/wireless/intersil/p54/p54pci.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/net/wireless/intersil/p54/p54pci.c
+++ b/drivers/net/wireless/intersil/p54/p54pci.c
@@ -333,10 +333,12 @@ static void p54p_tx(struct ieee80211_hw
struct p54p_desc *desc;
dma_addr_t mapping;
u32 idx, i;
+ __le32 device_addr;
spin_lock_irqsave(&priv->lock, flags);
idx = le32_to_cpu(ring_control->host_idx[1]);
i = idx % ARRAY_SIZE(ring_control->tx_data);
+ device_addr = ((struct p54_hdr *)skb->data)->req_id;
mapping = dma_map_single(&priv->pdev->dev, skb->data, skb->len,
DMA_TO_DEVICE);
@@ -350,7 +352,7 @@ static void p54p_tx(struct ieee80211_hw
desc = &ring_control->tx_data[i];
desc->host_addr = cpu_to_le32(mapping);
- desc->device_addr = ((struct p54_hdr *)skb->data)->req_id;
+ desc->device_addr = device_addr;
desc->len = cpu_to_le16(skb->len);
desc->flags = 0;
Patches currently in stable-queue which might be from baijiaju@xxxxxxxxxxxxxxx are
queue-5.9/p54-avoid-accessing-the-data-mapped-to-streaming-dma.patch
