Re: [PATCH] phy: rockchip-inno-usb2: Fix otg port initialization

[Samuel Holland]

On 9/17/22 11:58, Mikhail Rudenko wrote:
> There are two issues in rockchip_usb2phy_otg_port_init(): (1) even if
> devm_extcon_register_notifier() returns error, the code proceeds to
> the next if statement and (2) if no extcon is defined in of_node, the
> return value of property_enabled() is reused as the return value of
> the whole function. If the return value of property_enable() is
> nonzero, (2) results in an unexpected probe failure and kernel panic
> in delayed work:

This should be fixed by the following patch which is accepted already:

https://lore.kernel.org/lkml/20220902184543.1234835-1-pgwipeout@xxxxxxxxx/

> 
>     Unable to handle kernel NULL pointer dereference at virtual address 00000000
>     Mem abort info:
>       ESR = 0x0000000086000006
>       EC = 0x21: IABT (current EL), IL = 32 bits
>       SET = 0, FnV = 0
>       EA = 0, S1PTW = 0
>       FSC = 0x06: level 2 translation fault
>     user pgtable: 4k pages, 48-bit VAs, pgdp=00000000019dc000
>     [0000000000000000] pgd=080000000131a003, p4d=080000000131a003, pud=080000000
>     Internal error: Oops: 86000006 [#1] PREEMPT SMP
>     Modules linked in: ipv6
>     CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc5 #114
>     Hardware name: FriendlyElec NanoPi M4 (DT)
>     pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>     pc : 0x0
>     lr : call_timer_fn.constprop.0+0x24/0x80
>     sp : ffff80000a40ba40
>     x29: ffff80000a40ba40 x28: 0000000000000000 x27: ffff80000a40baf0
>     x26: ffff800009e779c0 x25: ffff00007fb28070 x24: ffff00007fb28028
>     x23: ffff80000a40baf0 x22: 0000000000000000 x21: 0000000000000101
>     x20: ffff0000006ad880 x19: 0000000000000000 x18: 0000000000000006
>     x17: ffff8000761af000 x16: ffff80000800c000 x15: 0000000000004000
>     x14: ffff0000006ad880 x13: 000000000000030a x12: 0000000000000000
>     x11: ffff8000761af000 x10: ffff80000800bf40 x9 : ffff00007fb2d038
>     x8 : 0000000000000001 x7 : 0000000000000009 x6 : 0000000000000240
>     x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000200
>     x2 : 000000003fffffff x1 : 0000000000000000 x0 : ffff0000016c9710
>     Call trace:
>      0x0
>      __run_timers+0x220/0x264
>      run_timer_softirq+0x20/0x40
>      __do_softirq+0x10c/0x298
>      __irq_exit_rcu+0xec/0xf4
>      irq_exit_rcu+0x10/0x1c
>      el1_interrupt+0x38/0x70
>      el1h_64_irq_handler+0x18/0x24
>      el1h_64_irq+0x64/0x68
>      cpuidle_enter_state+0x130/0x2fc
>      cpuidle_enter+0x38/0x50
>      do_idle+0x22c/0x2c0
>      cpu_startup_entry+0x24/0x30
>      secondary_start_kernel+0x130/0x14c
>      __secondary_switched+0xb0/0xb4
>     Code: bad PC value
>     ---[ end trace 0000000000000000 ]---
>     Kernel panic - not syncing: Oops: Fatal exception in interrupt
>     SMP: stopping secondary CPUs
>     Kernel Offset: disabled
>     CPU features: 0x4000,0820b021,00001086
>     Memory Limit: none
>     ---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---
> 
> Refactor the control flow to avoid both issues. Since the code below
> out: label does no cleanup, return error codes immediately instead of
> using gotos and return success at the end of the function.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 8dc60f8da22f ("phy: rockchip-inno-usb2: Sync initial otg state")
> Signed-off-by: Mikhail Rudenko <mike.rudenko@xxxxxxxxx>
> ---
>  drivers/phy/rockchip/phy-rockchip-inno-usb2.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c b/drivers/phy/rockchip/phy-rockchip-inno-usb2.c
> index 0b1e9337ee8e..d31b35d55927 100644
> --- a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c
> +++ b/drivers/phy/rockchip/phy-rockchip-inno-usb2.c
> @@ -1144,8 +1144,7 @@ static int rockchip_usb2phy_otg_port_init(struct rockchip_usb2phy *rphy,
>  	rport->mode = of_usb_get_dr_mode_by_phy(child_np, -1);
>  	if (rport->mode == USB_DR_MODE_HOST ||
>  	    rport->mode == USB_DR_MODE_UNKNOWN) {
> -		ret = 0;
> -		goto out;
> +		return 0;
>  	}
>  
>  	INIT_DELAYED_WORK(&rport->chg_work, rockchip_chg_detect_work);
> @@ -1154,7 +1153,7 @@ static int rockchip_usb2phy_otg_port_init(struct rockchip_usb2phy *rphy,
>  	ret = rockchip_usb2phy_port_irq_init(rphy, rport, child_np);
>  	if (ret) {
>  		dev_err(rphy->dev, "failed to init irq for host port\n");
> -		goto out;
> +		return ret;
>  	}
>  
>  	if (!IS_ERR(rphy->edev)) {
> @@ -1162,8 +1161,10 @@ static int rockchip_usb2phy_otg_port_init(struct rockchip_usb2phy *rphy,
>  
>  		ret = devm_extcon_register_notifier(rphy->dev, rphy->edev,
>  					EXTCON_USB_HOST, &rport->event_nb);
> -		if (ret)
> +		if (ret) {
>  			dev_err(rphy->dev, "register USB HOST notifier failed\n");
> +			return ret;
> +		}
>  
>  		if (!of_property_read_bool(rphy->dev->of_node, "extcon")) {
>  			/* do initial sync of usb state */
> @@ -1172,8 +1173,7 @@ static int rockchip_usb2phy_otg_port_init(struct rockchip_usb2phy *rphy,
>  		}
>  	}
>  
> -out:
> -	return ret;
> +	return 0;
>  }
>  
>  static int rockchip_usb2phy_probe(struct platform_device *pdev)

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