Re: [PATCH] Revert "usb: dwc3: qcom: Add support to skip phy management by USB core"

[Shawn Guo <shengchao.guo@oss.qualcomm.com>]

On Wed, Sep 09, 2026 at 03:19:10PM +0530, Krishna Kurapati wrote:
> This reverts commit be7b1c68cd3e4fc0f5a4e1b85696de1052f21f2f.
> 
> Commit be7b1c68cd3e ("usb: dwc3: qcom: Add support to skip phy management by USB core")
> is causing a regression on qualcomm platforms.
> 
> During role switch it tends to cause the following crash:
> 
> [    5.620951] refcount_t: underflow; use-after-free.
> [    5.621114] Call trace:
> [    5.621115]  refcount_warn_saturate+0xd8/0x140 (P)
> [    5.621117]  kobject_put+0x11c/0x230
> [    5.621121]  software_node_notify_remove+0xdc/0xf8
> [    5.621124]  device_del+0x1dc/0x328
> [    5.621126]  usb_disconnect+0x1d8/0x348
> [    5.621129]  usb_remove_hcd+0x100/0x2a8
> [    5.621131]  xhci_plat_remove+0x8c/0x170
> [    5.621134]  platform_remove+0x28/0x40
> [    5.621135]  device_release_driver_internal+0x174/0x290
> [    5.621138]  device_release_driver+0x20/0x38
> [    5.621140]  bus_remove_device+0x19c/0x1f8
> [    5.621142]  device_del+0x1c4/0x328
> [    5.621143]  platform_device_unregister+0x34/0xc0
> [    5.621145]  dwc3_host_exit+0x50/0x70
> [    5.621146]  __dwc3_set_mode+0xa4/0x378
> 
> [    5.644535] Unable to handle kernel paging request at virtual address
> [    5.644657] Workqueue: events_freezable __dwc3_set_mode
> [    5.644664] pc : __pi_strcmp+0x9c/0x140
> [    5.644668] lr : software_node_property_present+0x60/0x98
> [    5.644697] Call trace:
> [    5.644698]  __pi_strcmp+0x9c/0x140 (P)
> [    5.644700]  device_property_present+0x9c/0xc0
> [    5.644703]  dwc3_gadget_init+0x230/0x7b0
> [    5.644704]  __dwc3_set_mode+0x314/0x378
> [    5.644707]  process_scheduled_works+0x1b8/0x538
> [    5.644710]  worker_thread+0x1fc/0x2f8
> [    5.644711]  kthread+0x114/0x148
> [    5.644713]  ret_from_fork+0x10/0x20
> 
> Revert skipping of usb core phy management for Qualcomm platforms to avoid
> the above issues.
> 
> Reported-by: Val Packett <val@packett.cool>
> Closes: https://lore.kernel.org/all/f9926203-ee69-4e18-b6c7-95261ba10807@packett.cool/
> Signed-off-by: Krishna Kurapati <krishna.kurapati@oss.qualcomm.com>

I'm seeing a duplicate sysfs filename issue on Nord platform. This revert
fixes it, so:

Tested-by: Shawn Guo <shengchao.guo@oss.qualcomm.com>

[    6.412085] sysfs: cannot create duplicate filename '/devices/platform/soc@0/a400000.usb/software_node'
[    6.412088] CPU: 3 UID: 0 PID: 128 Comm: kworker/u73:3 Not tainted 7.3.0-rc2-next-20260908-00064-gde909f9bbb2a #16 PREEMPT(full)
[    6.412090] Hardware name: Qualcomm Technologies, Inc. SA8797P Ride Embedded (DT)
[    6.412091] Workqueue: events_unbound deferred_probe_work_func
[    6.412098] Call trace:
[    6.412099]  show_stack+0x18/0x24 (C)
[    6.412103]  dump_stack_lvl+0x74/0x8c
[    6.412107]  dump_stack+0x18/0x24
[    6.412109]  sysfs_warn_dup+0x64/0x80
[    6.412112]  sysfs_do_create_link_sd+0xf0/0xf8
[    6.412114]  sysfs_create_link+0x20/0x40
[    6.412116]  software_node_notify+0xb0/0x100
[    6.412117]  device_create_managed_software_node+0xec/0x108
[    6.412119]  dwc3_qcom_set_swnode+0x5c/0x8c
[    6.412122]  dwc3_qcom_probe+0x4d4/0x9c4
[    6.412123]  platform_probe+0x5c/0x9c
[    6.412125]  really_probe+0xbc/0x29c
[    6.412127]  __driver_probe_device+0x16c/0x19c
[    6.412129]  driver_probe_device+0x3c/0x114
[    6.412131]  __device_attach_driver+0xb8/0x118
[    6.412132]  bus_for_each_drv+0x88/0xe8
[    6.412134]  __device_attach+0xa0/0x190
[    6.412136]  device_initial_probe+0x50/0x54
[    6.412137]  bus_probe_device+0x38/0xa0
[    6.412139]  deferred_probe_work_func+0x88/0xc0
[    6.412141]  process_one_work+0x180/0x2dc
[    6.412143]  worker_thread+0x188/0x300
[    6.412145]  kthread+0x118/0x124
[    6.412146]  ret_from_fork+0x10/0x20