usb 6-1: USB disconnect, device number 2
BUG: kernel NULL pointer dereference, address: 0000000000000590
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 10bb1b067 P4D 10bb1b067 PUD 10be25067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 4904 Comm: kworker/0:3 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event

RIP: 0010:__list_del_entry_valid+0xa/0x50 lib/list_debug.c:43
Code: 89 c1 48 89 fe 48 c7 c7 60 55 7b 84 e8 70 cc 70 01 0f 0b 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 48 b9 00 01 00 00 00 00 ad de <48> 8b 07 48 8b 57 08 48 39 c8 0f 84 c4 72 77 01 48 b9 22 01 00 00
RSP: 0018:ffffc90000d77a00 EFLAGS: 00010286
RAX: ffffffff81e6f0f0 RBX: 0000000000000000 RCX: dead000000000100
RDX: 0000000000000001 RSI: ffffffff846ac8ac RDI: 0000000000000590
RBP: ffff88811ed67a00 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000006 R12: ffffffff8504f680
R13: ffff88811ee4d0d0 R14: 0000000000000000 R15: ffff88811ee74cb8
FS:  0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000590 CR3: 000000010bed0000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __list_del_entry include/linux/list.h:132 [inline]
 list_del include/linux/list.h:146 [inline]
 gpiodevice_release+0x11/0x80 drivers/gpio/gpiolib.c:477
 device_release+0x2b/0x80 drivers/base/core.c:2055
 kobject_cleanup lib/kobject.c:705 [inline]
 kobject_release lib/kobject.c:736 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x7c/0x1c0 lib/kobject.c:753
 release_nodes+0x229/0x270 drivers/base/devres.c:523
 __device_release_driver drivers/base/dd.c:1160 [inline]
 device_release_driver_internal+0xff/0x1d0 drivers/base/dd.c:1187
 bus_remove_device+0xea/0x160 drivers/base/bus.c:533
 device_del+0x186/0x3e0 drivers/base/core.c:3363
 platform_device_del.part.11+0xe/0x60 drivers/base/platform.c:783
 platform_device_del drivers/base/platform.c:820 [inline]
 platform_device_unregister+0x17/0x30 drivers/base/platform.c:821
 mfd_remove_devices_fn+0x3f/0x50 drivers/mfd/mfd-core.c:375
 device_for_each_child_reverse+0x54/0x90 drivers/base/core.c:3526
 mfd_remove_devices+0x2d/0x50 drivers/mfd/mfd-core.c:391
 vprbrd_disconnect+0x1a/0x60 drivers/mfd/viperboard.c:111
 usb_unbind_interface+0x6e/0x250 drivers/usb/core/driver.c:458
 __device_release_driver drivers/base/dd.c:1156 [inline]
 device_release_driver_internal+0xef/0x1d0 drivers/base/dd.c:1187
 bus_remove_device+0xea/0x160 drivers/base/bus.c:533
 device_del+0x186/0x3e0 drivers/base/core.c:3363
 usb_disable_device+0xa4/0x220 drivers/usb/core/message.c:1413
 usb_disconnect+0xbc/0x2c0 drivers/usb/core/hub.c:2218
 hub_port_connect drivers/usb/core/hub.c:5074 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
 port_event drivers/usb/core/hub.c:5509 [inline]
 hub_event+0xa3e/0x15f0 drivers/usb/core/hub.c:5591
 process_one_work+0x293/0x600 kernel/workqueue.c:2275
 process_scheduled_works kernel/workqueue.c:2337 [inline]
 worker_thread+0x1ff/0x380 kernel/workqueue.c:2423
 kthread+0x144/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
CR2: 0000000000000590
---[ end trace 111ebd768b6d2b88 ]---
RIP: 0010:__list_del_entry_valid+0xa/0x50 lib/list_debug.c:43
Code: 89 c1 48 89 fe 48 c7 c7 60 55 7b 84 e8 70 cc 70 01 0f 0b 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 48 b9 00 01 00 00 00 00 ad de <48> 8b 07 48 8b 57 08 48 39 c8 0f 84 c4 72 77 01 48 b9 22 01 00 00
RSP: 0018:ffffc90000d77a00 EFLAGS: 00010286
RAX: ffffffff81e6f0f0 RBX: 0000000000000000 RCX: dead000000000100
RDX: 0000000000000001 RSI: ffffffff846ac8ac RDI: 0000000000000590
RBP: ffff88811ed67a00 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000006 R12: ffffffff8504f680
R13: ffff88811ee4d0d0 R14: 0000000000000000 R15: ffff88811ee74cb8
FS:  0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000590 CR3: 000000010bed0000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400