[PATCH] net: stmmac: dump gmac4 DMA registers correctly

[Jakub Kicinski]

On Fri, 28 Jan 2022 16:36:42 +0100 Camel Guo wrote:
> From: Camel Guo <camelg at axis.com>
> 
> Unlike gmac100, gmac1000, gmac4 has 27 DMA registers and they are
> located at DMA_CHAN_BASE_ADDR (0x1100). In order for ethtool to dump
> gmac4 DMA registers correctly, this commit checks if a net_device has
> gmac4 and uses different logic to dump its DMA registers.
> 
> This fixes the following KASAN warning, which can normally be triggered
> by a command similar like "ethtool -d eth0":
> 
> BUG: KASAN: vmalloc-out-of-bounds in dwmac4_dump_dma_regs+0x6d4/0xb30
> Write of size 4 at addr ffffffc010177100 by task ethtool/1839
>  kasan_report+0x200/0x21c
>  __asan_report_store4_noabort+0x34/0x60
>  dwmac4_dump_dma_regs+0x6d4/0xb30
>  stmmac_ethtool_gregs+0x110/0x204
>  ethtool_get_regs+0x200/0x4b0
>  dev_ethtool+0x1dac/0x3800
>  dev_ioctl+0x7c0/0xb50
>  sock_ioctl+0x298/0x6c4
>  ...
> 
> Signed-off-by: Camel Guo <camelg at axis.com>

Can we get a Fixes tag for this? If it was always broken the Fixes tag
should point to the commit which added gmac4 support.