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References: <20240226100502.1845284-1-michael@amarulasolutions.com> <2024022609-groom-passably-909c@gregkh>
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From: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
Date: Mon, 26 Feb 2024 11:19:36 +0100
Message-ID: <CAOf5uwnd+qh0PZgXhPN21Eng7HN+_Vjgjad7UxZ79-b1gZEhOw@mail.gmail.com>
Subject: Re: [PATCH V3] usb: dwc3: gadget: Fix suspend/resume warning when
 no-gadget is connected
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>, linux-usb@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-amarula@amarulasolutions.com, 
	stable@vger.kernel.org
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Hi Greg

On Mon, Feb 26, 2024 at 11:14=E2=80=AFAM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Mon, Feb 26, 2024 at 11:05:02AM +0100, Michael Trimarchi wrote:
> > This patch avoid to disconnect an already gadget in not connected state
> >
> > [   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 d=
wc3_ep0_out_start+0xcc/0xd4
> > [   45.601102] Modules linked in: cfg80211 rfkill ipv6 rpmsg_ctrl rpmsg=
_char crct10dif_ce rti_wdt k3_j72xx_bandgap rtc_ti_k3 omap_mailbox sa2ul au=
thenc [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 BT=
YPE=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: ffff800=
0808dc630
> > [   45.601200] x26: 0000000000000002 x25: ffff800082530a44 x24: 0000000=
000000000
> > [   45.601210] x23: ffff000000e079a0 x22: ffff000000e07a68 x21: 0000000=
000000001
> > [   45.601219] x20: ffff000000e07880 x19: ffff000000e07880 x18: 0000000=
000000040
> > [   45.601229] x17: ffff7fff8e1ce000 x16: ffff800080000000 x15: fffffff=
ffffe5260
> > [   45.601239] x14: 0000000000000000 x13: 206e6f204c4c4154 x12: 5320746=
573206f74
> > [   45.601249] x11: 0000000000000001 x10: 000000000000000a x9 : ffff800=
083273930
> > [   45.601259] x8 : 000000000000000a x7 : ffffffffffff3f0c x6 : fffffff=
fffff3f00
> > [   45.601268] x5 : ffffffffffff3f0c x4 : 0000000000000000 x3 : 0000000=
000000000
> > [   45.601278] x2 : 0000000000000000 x1 : ffff000004e7e600 x0 : 0000000=
0ffffff92
> > [   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 with a usbnet gadget
> >
> > Fixes: 61a348857e86 ("usb: dwc3: gadget: Fix NULL pointer dereference i=
n dwc3_gadget_suspend)
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
> > ---
> > V2->V3:
> >       - Change the logic of the patch using the gadget connected state
> >       - Change of the commit message
> > V1->V2:
> >       - Add stable in CC
> > ---
> >  drivers/usb/dwc3/gadget.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index 4c8dd6724678..a7316a1703ad 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -2650,6 +2650,15 @@ static int dwc3_gadget_soft_disconnect(struct dw=
c3 *dwc)
> >       int ret;
> >
> >       spin_lock_irqsave(&dwc->lock, flags);
> > +     /*
> > +      * Attempt to disconnect a no connected gadget
>
> What does this mean?  And why a 3 line comment?
>
> > +      */
> > +     if (!dwc->connected) {
> > +             dev_warn(dwc->dev, "No connected device\n");
>
> You are printing while a spinlock is held?  What can userspace do with
> this message?

I will drop it.

>
> > +             spin_unlock_irqrestore(&dwc->lock, flags);
> > +             return 0;
>
> No error handling?  Why not?

The function tries to disconnect an already disconnected gadget, so in
this case is a nop. If we want to handle
an error I can check the impact on the dwc3 gadget.

Michael

>
> thanks,
>
> greg k-h


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