linux-kernel - Re: [PATCH] usb: dwc3: gadget: Move vbus draw to workqueue context

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAGZ6i=3ZJ3aihjmXnPq9C-mpVYa6rqzfWTn3qXmavYUiZtE24A@mail.gmail.com>
Date: Wed, 4 Feb 2026 11:59:41 +0800
From: Kyle Tso <kyletso@...gle.com>
To: Prashanth K <prashanth.k@....qualcomm.com>
Cc: Thinh Nguyen <Thinh.Nguyen@...opsys.com>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, linux-usb@...r.kernel.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] usb: dwc3: gadget: Move vbus draw to workqueue context

On Thu, Jan 29, 2026 at 7:16 PM Prashanth K
<prashanth.k@....qualcomm.com> wrote:
>
> Currently dwc3_gadget_vbus_draw() can be called from atomic
> context, which in turn invokes power-supply-core APIs. And
> some these PMIC APIs have operations that may sleep, leading
> to kernel panic.
>
> Fix this by moving the vbus_draw into a workqueue context.
>
> Fixes: 66e0ea341a2a ("usb: dwc3: core: Defer the probe until USB power supply ready")

I think the following patch is the one to fix:

https://lore.kernel.org/all/20210222115149.3606776-3-raychi@google.com/

> Cc: stable@...r.kernel.org
> Signed-off-by: Prashanth K <prashanth.k@....qualcomm.com>
> ---
>  drivers/usb/dwc3/core.c   | 19 ++++++++++++++++++-
>  drivers/usb/dwc3/core.h   |  4 ++++
>  drivers/usb/dwc3/gadget.c |  8 +++-----
>  3 files changed, 25 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index f32b67bf73a4..c9af126b9695 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -2155,6 +2155,20 @@ static int dwc3_get_num_ports(struct dwc3 *dwc)
>         return 0;
>  }
>
> +static void dwc3_vbus_draw_work(struct work_struct *work)
> +{
> +       struct dwc3 *dwc = container_of(work, struct dwc3, vbus_draw_work);
> +       union power_supply_propval val = {0};
> +       int ret;
> +
> +       val.intval = 1000 * (dwc->vbus_draw_current);
> +       ret = power_supply_set_property(dwc->usb_psy, POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, &val);
> +
> +       if (ret < 0)
> +               dev_dbg(dwc->dev, "Error (%d) setting vbus draw (%d mA)\n",
> +                       ret, dwc->vbus_draw_current);
> +}
> +
>  static struct power_supply *dwc3_get_usb_power_supply(struct dwc3 *dwc)
>  {
>         struct power_supply *usb_psy;
> @@ -2169,6 +2183,7 @@ static struct power_supply *dwc3_get_usb_power_supply(struct dwc3 *dwc)
>         if (!usb_psy)
>                 return ERR_PTR(-EPROBE_DEFER);
>
> +       INIT_WORK(&dwc->vbus_draw_work, dwc3_vbus_draw_work);
>         return usb_psy;
>  }
>
> @@ -2395,8 +2410,10 @@ void dwc3_core_remove(struct dwc3 *dwc)
>
>         dwc3_free_event_buffers(dwc);
>
> -       if (dwc->usb_psy)
> +       if (dwc->usb_psy) {
> +               cancel_work_sync(&dwc->vbus_draw_work);
>                 power_supply_put(dwc->usb_psy);
> +       }
>  }
>  EXPORT_SYMBOL_GPL(dwc3_core_remove);
>
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 08cc6f2b5c23..052fb18c6b5c 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1178,6 +1178,8 @@ struct dwc3_glue_ops {
>   * @wakeup_pending_funcs: Indicates whether any interface has requested for
>   *                      function wakeup in bitmap format where bit position
>   *                      represents interface_id.
> + * @vbus_draw_work: Workqueue used for scheduling vbus draw work
> + * @vbus_draw_current: How much current to draw from vbus, in milliAmperes.
>   */
>  struct dwc3 {
>         struct work_struct      drd_work;
> @@ -1413,6 +1415,8 @@ struct dwc3 {
>         struct dentry           *debug_root;
>         u32                     gsbuscfg0_reqinfo;
>         u32                     wakeup_pending_funcs;
> +       struct work_struct      vbus_draw_work;
> +       unsigned int            vbus_draw_current;
>  };
>
>  #define INCRX_BURST_MODE 0
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 9355c952c140..03d8a3a151e0 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -3124,8 +3124,6 @@ static void dwc3_gadget_set_ssp_rate(struct usb_gadget *g,
>  static int dwc3_gadget_vbus_draw(struct usb_gadget *g, unsigned int mA)
>  {
>         struct dwc3             *dwc = gadget_to_dwc(g);
> -       union power_supply_propval      val = {0};
> -       int                             ret;
>
>         if (dwc->usb2_phy)
>                 return usb_phy_set_power(dwc->usb2_phy, mA);
> @@ -3133,10 +3131,10 @@ static int dwc3_gadget_vbus_draw(struct usb_gadget *g, unsigned int mA)
>         if (!dwc->usb_psy)
>                 return -EOPNOTSUPP;
>
> -       val.intval = 1000 * mA;
> -       ret = power_supply_set_property(dwc->usb_psy, POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, &val);
> +       dwc->vbus_draw_current = mA;
> +       schedule_work(&dwc->vbus_draw_work);
>
> -       return ret;
> +       return 0;
>  }
>
>  /**
> --
> 2.34.1
>
>