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References: <20240226070348.1703879-1-michael@amarulasolutions.com>
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From: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
Date: Mon, 26 Feb 2024 08:53:21 +0100
Message-ID: <CAOf5uw=P0UYXP8ujHpF+hnGR_cg90gqv9na7cVH1sQ-BtEgrTA@mail.gmail.com>
Subject: Re: [PATCH V2] usb: dwc3: gadget: Fix suspend/resume warning when
 no-gadget is connected
To: Thinh Nguyen <Thinh.Nguyen@synopsys.com>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-amarula@amarulasolutions.com, stable@vger.kernel.org
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Hi all

Please don't review, I'm not happy with it and even it's broken. I
need to find better solution

On Mon, Feb 26, 2024 at 8:03=E2=80=AFAM Michael Trimarchi
<michael@amarulasolutions.com> wrote:
>
> This patch restore the logic but protects the variable using a spinlock
> without moving the code
>
> [   45.597274] dwc3 31000000.usb: wait for SETUP phase timed out
> [   45.599140] dwc3 31000000.usb: failed to set STALL on ep0out
> [   45.601069] ------------[ cut here ]------------
> [   45.601073] WARNING: CPU: 0 PID: 150 at drivers/usb/dwc3/ep0.c:289 dwc=
3_ep0_out_start+0xcc/0xd4
> [   45.601102] Modules linked in: cfg80211 rfkill ipv6 rpmsg_ctrl rpmsg_c=
har crct10dif_ce rti_wdt k3_j72xx_bandgap rtc_ti_k3 omap_mailbox sa2ul auth=
enc [last unloaded: ti_k3_r5_remoteproc]
> [   45.601151] CPU: 0 PID: 150 Comm: sh Not tainted 6.8.0-rc5 #1
> [   45.601159] Hardware name: BSH - CCM-M3 (DT)
> [   45.601164] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYP=
E=3D--)
> [   45.601172] pc : dwc3_ep0_out_start+0xcc/0xd4
> [   45.601179] lr : dwc3_ep0_out_start+0x50/0xd4
> [   45.601186] sp : ffff8000832739e0
> [   45.601189] x29: ffff8000832739e0 x28: ffff800082a21000 x27: ffff80008=
08dc630
> [   45.601200] x26: 0000000000000002 x25: ffff800082530a44 x24: 000000000=
0000000
> [   45.601210] x23: ffff000000e079a0 x22: ffff000000e07a68 x21: 000000000=
0000001
> [   45.601219] x20: ffff000000e07880 x19: ffff000000e07880 x18: 000000000=
0000040
> [   45.601229] x17: ffff7fff8e1ce000 x16: ffff800080000000 x15: fffffffff=
ffe5260
> [   45.601239] x14: 0000000000000000 x13: 206e6f204c4c4154 x12: 532074657=
3206f74
> [   45.601249] x11: 0000000000000001 x10: 000000000000000a x9 : ffff80008=
3273930
> [   45.601259] x8 : 000000000000000a x7 : ffffffffffff3f0c x6 : fffffffff=
fff3f00
> [   45.601268] x5 : ffffffffffff3f0c x4 : 0000000000000000 x3 : 000000000=
0000000
> [   45.601278] x2 : 0000000000000000 x1 : ffff000004e7e600 x0 : 00000000f=
fffff92
> [   45.601289] Call trace:
> [   45.601293]  dwc3_ep0_out_start+0xcc/0xd4
> [   45.601301]  dwc3_ep0_stall_and_restart+0x98/0xbc
> [   45.601309]  dwc3_ep0_reset_state+0x5c/0x88
> [   45.601315]  dwc3_gadget_soft_disconnect+0x144/0x160
> [   45.601323]  dwc3_gadget_suspend+0x18/0xb0
> [   45.601329]  dwc3_suspend_common+0x5c/0x18c
> [   45.601341]  dwc3_suspend+0x20/0x44
> [   45.601350]  platform_pm_suspend+0x2c/0x6c
> [   45.601360]  __device_suspend+0x10c/0x34c
> [   45.601372]  dpm_suspend+0x1a8/0x240
> [   45.601382]  dpm_suspend_start+0x80/0x9c
> [   45.601391]  suspend_devices_and_enter+0x1c4/0x584
> [   45.601402]  pm_suspend+0x1b0/0x264
> [   45.601408]  state_store+0x80/0xec
> [   45.601415]  kobj_attr_store+0x18/0x2c
> [   45.601426]  sysfs_kf_write+0x44/0x54
> [   45.601434]  kernfs_fop_write_iter+0x120/0x1ec
> [   45.601445]  vfs_write+0x23c/0x358
> [   45.601458]  ksys_write+0x70/0x104
> [   45.601467]  __arm64_sys_write+0x1c/0x28
> [   45.601477]  invoke_syscall+0x48/0x114
> [   45.601488]  el0_svc_common.constprop.0+0x40/0xe0
> [   45.601498]  do_el0_svc+0x1c/0x28
> [   45.601506]  el0_svc+0x34/0xb8
> [   45.601516]  el0t_64_sync_handler+0x100/0x12c
> [   45.601522]  el0t_64_sync+0x190/0x194
> [   45.601531] ---[ end trace 0000000000000000 ]---
> [   45.608794] Disabling non-boot CPUs ...
> [   45.611029] psci: CPU1 killed (polled 0 ms)
> [   45.611837] Enabling non-boot CPUs ...
> [   45.612247] Detected VIPT I-cache on CPU1
>
> Tested on a am62x board
>
> Fixes: 61a348857e86 ("usb: dwc3: gadget: Fix NULL pointer dereference in =
dwc3_gadget_suspend)
> Cc: stable@vger.kernel.org
> Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
> ---
> V1->V2:
>         Add cc to stable
> ---
>  drivers/usb/dwc3/gadget.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 4c8dd6724678..4c88e44127b5 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -4703,13 +4703,19 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
>         unsigned long flags;
>         int ret;
>
> +       spin_lock_irqsave(&dwc->lock, flags);
> +       if (!dwc->gadget_driver) {
> +               spin_unlock_irqrestore(&dwc->lock, flags);
> +               return 0;
> +       }
> +       spin_unlock_irqrestore(&dwc->lock, flags);
> +
>         ret =3D dwc3_gadget_soft_disconnect(dwc);
>         if (ret)
>                 goto err;
>
>         spin_lock_irqsave(&dwc->lock, flags);
> -       if (dwc->gadget_driver)
> -               dwc3_disconnect_gadget(dwc);
> +       dwc3_disconnect_gadget(dwc);
>         spin_unlock_irqrestore(&dwc->lock, flags);
>
>         return 0;
> --
> 2.40.1
>


--=20
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael@amarulasolutions.com
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