[PATCH net-next] net: stmmac: support FPE link partner hand-shaking procedure

[Wong, Vee Khee]

On Thu, 25 March 2021, 11:13PM +800, Marek Szyprowski wrote: 
> This patch landed in today's linux-next as commit 5a5586112b92 ("net:
> stmmac: support FPE link partner hand-shaking procedure"). It causes the
> following NULL pointer dereference issue on various Amlogic SoC based
> boards:
> 
>   meson8b-dwmac ff3f0000.ethernet eth0: PHY [0.0:00] driver [RTL8211F
> Gigabit Ethernet] (irq=35)
>   meson8b-dwmac ff3f0000.ethernet eth0: No Safety Features support
> found
>   meson8b-dwmac ff3f0000.ethernet eth0: PTP not supported by HW
>   meson8b-dwmac ff3f0000.ethernet eth0: configuring for phy/rgmii link
> mode
>   Unable to handle kernel NULL pointer dereference at virtual address
> 0000000000000001
>   Mem abort info:
> ...
>   user pgtable: 4k pages, 48-bit VAs, pgdp=00000000044eb000
>   [0000000000000001] pgd=0000000000000000, p4d=0000000000000000
>   Internal error: Oops: 96000004 [#1] PREEMPT SMP
>   Modules linked in: dw_hdmi_i2s_audio dw_hdmi_cec meson_gxl realtek
> meson_gxbb_wdt snd_soc_meson_axg_sound_card dwmac_generic
> axg_audio
> meson_dw_hdmi crct10dif_ce snd_soc_meson_card_utils
> snd_soc_meson_axg_tdmout panfrost rc_odroid gpu_sched
> reset_meson_audio_arb meson_ir snd_soc_meson_g12a_tohdmitx
> snd_soc_meson_axg_frddr sclk_div clk_phase snd_soc_meson_codec_glue
> dwmac_meson8b snd_soc_meson_axg_fifo stmmac_platform meson_rng
> meson_drm
> stmmac rtc_meson_vrtc rng_core meson_canvas pwm_meson dw_hdmi
> mdio_mux_meson_g12a pcs_xpcs snd_soc_meson_axg_tdm_interface
> snd_soc_meson_axg_tdm_formatter nvmem_meson_efuse
> display_connector
>   CPU: 1 PID: 7 Comm: kworker/u8:0 Not tainted 5.12.0-rc4-next-20210325+
> #2747
>   Hardware name: Hardkernel ODROID-C4 (DT)
>   Workqueue: events_power_efficient phylink_resolve
>   pstate: 20400009 (nzCv daif +PAN -UAO -TCO BTYPE=--)
>   pc : stmmac_mac_link_up+0x14c/0x348 [stmmac]
>   lr : stmmac_mac_link_up+0x284/0x348 [stmmac]
> ...
>   Call trace:
>    stmmac_mac_link_up+0x14c/0x348 [stmmac]
>    phylink_resolve+0x104/0x420
>    process_one_work+0x2a8/0x718
>    worker_thread+0x48/0x460
>    kthread+0x134/0x160
>    ret_from_fork+0x10/0x18
>   Code: b971ba60 350007c0 f958c260 f9402000 (39400401)
>   ---[ end trace 0c9deb6c510228aa ]---
> 
> 
> Best regards
> --
> Marek Szyprowski, PhD
> Samsung R&D Institute Poland

Sorry for that, we will submit a fix for this.

VK