Re: [PATCH RESEND v3 3/5] phy: renesas: rcar-gen3-usb2: Lock around hardware registers and driver data

[Claudiu Beznea]

On 6/3/26 16:22, Xia Fukun wrote:
> On 5/7/2025 8:50 PM, Claudiu wrote:
>
> > @@ -348,6 +349,8 @@ static ssize_t role_store(struct device *dev, struct device_attribute *attr,
> >   	bool is_b_device;
> >   	enum phy_mode cur_mode, new_mode;
> >   
> > +	guard(spinlock_irqsave)(&ch->lock);
> > +
> >   	if (!ch->is_otg_channel || !rcar_gen3_is_any_otg_rphy_initialized(ch))
> >   		return -EIO;
> >   
> > @@ -415,7 +418,7 @@ static void rcar_gen3_init_otg(struct rcar_gen3_chan *ch)
> >   		val = readl(usb2_base + USB2_ADPCTRL);
> >   		writel(val | USB2_ADPCTRL_IDPULLUP, usb2_base + USB2_ADPCTRL);
> >   	}
> > -	msleep(20);
> > +	mdelay(20);
> >   
> >   	writel(0xffffffff, usb2_base + USB2_OBINTSTA);
> >   	writel(ch->obint_enable_bits, usb2_base + USB2_OBINTEN);
> The fix for the rcar_gen3_init_otg function has not been backported to
> the 5.10-stable branch, which leads to a "scheduling while atomic" bug
> in that branch:
>
> rcar_gen3_phy_usb2_init()                    ← phy_init() callback
>    → guard(spinlock_irqsave)(&ch->lock)       ← acquires spinlock, disabling preemption + IRQs
>    → rcar_gen3_init_otg(ch)
>        → msleep(20)                           ← BUG: scheduling while atomic!
>
> The patch for 5.10 is available at the following link:
> https://web.git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/? 
> h=linux-5.10.y&id=0f86a559900fbe96af08a3a226a86fac27b02b8f
>
> Perhaps the stable patch for the 5.10 branch needs to be updated to
> fix this serious bug?

Sasha applied today the patch at [1] to solve this problem on v5.10.

Thank you,
Claudiu

[1] 
https://lore.kernel.org/all/20260501225859.504868-1-nobuhiro.iwamatsu.x90@mail.toshiba/