------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 3 PID: 59 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 3 UID: 0 PID: 59 Comm: kworker/3:1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: usb_hub_wq hub_event
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 88 e0 d7 fc 84 db 0f 85 66 ff ff ff e8 9b e5 d7 fc c6 05 57 1e b0 0b 01 90 48 c7 c7 00 9c 15 8c e8 a7 88 96 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 78 e5 d7 fc 0f b6 1d 32 1e b0 0b 31
RSP: 0018:ffffc900006f8be0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817a3388
RDX: ffff8880223d8000 RSI: ffffffff817a3395 RDI: 0000000000000001
RBP: ffff888032356ee8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888032356ee8
R13: ffff888039fc3400 R14: 0000000000000015 R15: 1ffff1100647b00c
FS: 0000000000000000(0000) GS:ffff8880d69b5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0b9b1a9a84 CR3: 000000004ecb9000 CR4: 0000000000352ef0
Call Trace:
__refcount_sub_and_test include/linux/refcount.h:400 [inline]
__refcount_dec_and_test include/linux/refcount.h:432 [inline]
refcount_dec_and_test include/linux/refcount.h:450 [inline]
p9_req_put+0x1ec/0x250 net/9p/client.c:404
req_done+0x1dc/0x2e0 net/9p/trans_virtio.c:147
vring_interrupt drivers/virtio/virtio_ring.c:2719 [inline]
vring_interrupt+0x31b/0x400 drivers/virtio/virtio_ring.c:2694
__handle_irq_event_percpu+0x22c/0x7d0 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
handle_edge_irq+0x3ca/0x9e0 kernel/irq/chip.c:855
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:310 [inline]
__common_interrupt+0xcd/0x2f0 arch/x86/kernel/irq.c:325
common_interrupt+0x61/0xe0 arch/x86/kernel/irq.c:318
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
RIP: 0010:handle_softirqs+0x1dd/0x8e0 kernel/softirq.c:565
Code: 88 6c 24 26 4c 89 7c 24 18 48 c7 c7 20 a8 ab 8b e8 c8 33 18 0a 65 66 c7 05 26 7f 5a 12 00 00 e8 d9 44 47 00 fb bb ff ff ff ff <49> c7 c7 c0 c0 20 8e 41 0f bc dc 83 c3 01 0f 85 a4 00 00 00 e9 b1
RSP: 0018:ffffc900006f8f28 EFLAGS: 00000206
RAX: 0000000000033228 RBX: 00000000ffffffff RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8de522e0 RDI: ffffffff8c162d00
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab6b97 R11: 0000000000000000 R12: 0000000000000200
R13: 000000000000000a R14: 1ffff920000df1ed R15: ffffed100447b000
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:console_flush_all+0x9a2/0xc60 kernel/printk/printk.c:3227
Code: 00 e8 f2 d5 28 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 30 ea 20 00 48 85 db 0f 85 55 01 00 00 e8 b2 ee 20 00 fb 4c 89 e0 <48> c1 e8 03 42 80 3c 38 00 0f 84 11 ff ff ff 4c 89 e7 e8 07 4f 87
RSP: 0018:ffffc90000acf188 EFLAGS: 00000293
RAX: ffffffff8f2ed5d8 RBX: 0000000000000000 RCX: ffffffff819aa010
RDX: ffff8880223d8000 RSI: ffffffff819aa01e RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8f2ed5d8
R13: ffffffff8f2ed580 R14: ffffc90000acf218 R15: dffffc0000000000
__console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
dev_vprintk_emit drivers/base/core.c:4914 [inline]
dev_printk_emit+0xfa/0x140 drivers/base/core.c:4925
__dev_printk+0xf5/0x270 drivers/base/core.c:4937
_dev_notice+0xe4/0x120 drivers/base/core.c:4982
usb_parse_endpoint drivers/usb/core/config.c:503 [inline]
usb_parse_interface drivers/usb/core/config.c:636 [inline]
usb_parse_configuration drivers/usb/core/config.c:849 [inline]
usb_get_configuration+0x4fb7/0x6530 drivers/usb/core/config.c:998
usb_enumerate_device drivers/usb/core/hub.c:2526 [inline]
usb_new_device+0x11d3/0x1a60 drivers/usb/core/hub.c:2664
hub_port_connect drivers/usb/core/hub.c:5566 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
port_event drivers/usb/core/hub.c:5870 [inline]
hub_event+0x2f34/0x4fe0 drivers/usb/core/hub.c:5952
process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
----------------
Code disassembly (best guess):
0: 88 6c 24 26 mov %ch,0x26(%rsp)
4: 4c 89 7c 24 18 mov %r15,0x18(%rsp)
9: 48 c7 c7 20 a8 ab 8b mov $0xffffffff8baba820,%rdi
10: e8 c8 33 18 0a call 0xa1833dd
15: 65 66 c7 05 26 7f 5a movw $0x0,%gs:0x125a7f26(%rip) # 0x125a7f45
1c: 12 00 00
1f: e8 d9 44 47 00 call 0x4744fd
24: fb sti
25: bb ff ff ff ff mov $0xffffffff,%ebx
* 2a: 49 c7 c7 c0 c0 20 8e mov $0xffffffff8e20c0c0,%r15 <-- trapping instruction
31: 41 0f bc dc bsf %r12d,%ebx
35: 83 c3 01 add $0x1,%ebx
38: 0f 85 a4 00 00 00 jne 0xe2
3e: e9 .byte 0xe9
3f: b1 .byte 0xb1