------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x111/0x130 lib/refcount.c:25, CPU#0: kworker/0:5/5227
Modules linked in:

CPU: 0 UID: 0 PID: 5227 Comm: kworker/0:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: usb_hub_wq hub_event

RIP: 0010:refcount_warn_saturate+0x111/0x130 lib/refcount.c:25
Code: cc e8 63 4d e5 fe 48 8d 3d 1c d5 27 08 67 48 0f b9 3a e8 52 4d e5 fe 5b 5d e9 0b 73 9f 04 e8 46 4d e5 fe 48 8d 3d 0f d5 27 08 <67> 48 0f b9 3a e8 35 4d e5 fe 5b 5d c3 cc cc cc cc 48 89 df e8 e6
RSP: 0018:ffffc9000309ef30 EFLAGS: 00010283

RAX: 00000000000588f4 RBX: ffff888121208028 RCX: ffffc90013322000
RDX: 0000000000100000 RSI: ffffffff82cc97da RDI: ffffffff8af46cf0
RBP: 0000000000000002 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000002 R11: 0000000000155cc0 R12: ffff88813b30e000
R13: ffff888121208028 R14: 0000000000000000 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8882686ce000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e323ffc CR3: 0000000115f4c000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __refcount_add include/linux/refcount.h:289 [inline]
 __refcount_inc include/linux/refcount.h:366 [inline]
 refcount_inc include/linux/refcount.h:383 [inline]
 get_task_struct include/linux/sched/task.h:116 [inline]
 kthread_stop+0x602/0x680 kernel/kthread.c:754
 rsi_kill_thread drivers/net/wireless/rsi/rsi_common.h:78 [inline]
 rsi_91x_deinit+0x102/0x1f0 drivers/net/wireless/rsi/rsi_91x_main.c:405
 rsi_probe+0xd27/0x1aa0 drivers/net/wireless/rsi/rsi_91x_usb.c:861
 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:583 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:661
 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833
 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:961
----------------
Code disassembly (best guess):
   0:	cc                   	int3
   1:	e8 63 4d e5 fe       	call   0xfee54d69
   6:	48 8d 3d 1c d5 27 08 	lea    0x827d51c(%rip),%rdi        # 0x827d529
   d:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  12:	e8 52 4d e5 fe       	call   0xfee54d69
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	e9 0b 73 9f 04       	jmp    0x49f7329
  1e:	e8 46 4d e5 fe       	call   0xfee54d69
  23:	48 8d 3d 0f d5 27 08 	lea    0x827d50f(%rip),%rdi        # 0x827d539
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e8 35 4d e5 fe       	call   0xfee54d69
  34:	5b                   	pop    %rbx
  35:	5d                   	pop    %rbp
  36:	c3                   	ret
  37:	cc                   	int3
  38:	cc                   	int3
  39:	cc                   	int3
  3a:	cc                   	int3
  3b:	48 89 df             	mov    %rbx,%rdi
  3e:	e8                   	.byte 0xe8
  3f:	e6                   	.byte 0xe6