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Date: Mon, 26 Feb 2024 11:14:53 +0100
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Michael Trimarchi <michael@amarulasolutions.com>
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
Subject: Re: [PATCH V3] usb: dwc3: gadget: Fix suspend/resume warning when
 no-gadget is connected
Message-ID: <2024022609-groom-passably-909c@gregkh>
References: <20240226100502.1845284-1-michael@amarulasolutions.com>
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In-Reply-To: <20240226100502.1845284-1-michael@amarulasolutions.com>

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 dwc3_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 authenc [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 BTYPE=--)
> [   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: ffff8000808dc630
> [   45.601200] x26: 0000000000000002 x25: ffff800082530a44 x24: 0000000000000000
> [   45.601210] x23: ffff000000e079a0 x22: ffff000000e07a68 x21: 0000000000000001
> [   45.601219] x20: ffff000000e07880 x19: ffff000000e07880 x18: 0000000000000040
> [   45.601229] x17: ffff7fff8e1ce000 x16: ffff800080000000 x15: fffffffffffe5260
> [   45.601239] x14: 0000000000000000 x13: 206e6f204c4c4154 x12: 5320746573206f74
> [   45.601249] x11: 0000000000000001 x10: 000000000000000a x9 : ffff800083273930
> [   45.601259] x8 : 000000000000000a x7 : ffffffffffff3f0c x6 : ffffffffffff3f00
> [   45.601268] x5 : ffffffffffff3f0c x4 : 0000000000000000 x3 : 0000000000000000
> [   45.601278] x2 : 0000000000000000 x1 : ffff000004e7e600 x0 : 00000000ffffff92
> [   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 in 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 dwc3 *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?

> +		spin_unlock_irqrestore(&dwc->lock, flags);
> +		return 0;

No error handling?  Why not?

thanks,

greg k-h