------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 0 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.8.0-rc1-syzkaller-00311-g3a5879d495b2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 d8 60 1e fd 84 db 0f 85 66 ff ff ff e8 9b 65 1e fd c6 05 4a 4c bb 0a 01 90 48 c7 c7 40 76 2f 8b e8 27 59 e4 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 78 65 1e fd 0f b6 1d 25 4c bb 0a 31
RSP: 0018:ffffc90000007bf8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff814e18f9
RDX: ffffffff8ce95a40 RSI: ffffffff814e1906 RDI: 0000000000000001
RBP: ffff88804b2c4140 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: dffffc0000000000
R13: ffff88804b2c4140 R14: ffff88801e172c00 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88802c600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000031831000 CR3: 000000002777e000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __refcount_sub_and_test include/linux/refcount.h:272 [inline]
 __refcount_dec_and_test include/linux/refcount.h:304 [inline]
 refcount_dec_and_test include/linux/refcount.h:322 [inline]
 p9_req_put+0x1f0/0x250 net/9p/client.c:401
 req_done+0x1e7/0x2e0 net/9p/trans_virtio.c:147
 vring_interrupt drivers/virtio/virtio_ring.c:2595 [inline]
 vring_interrupt+0x317/0x3f0 drivers/virtio/virtio_ring.c:2570
 __handle_irq_event_percpu+0x22a/0x750 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+0x261/0xcf0 kernel/irq/chip.c:831
 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline]
 handle_irq arch/x86/kernel/irq.c:238 [inline]
 __common_interrupt+0xdb/0x240 arch/x86/kernel/irq.c:257
 common_interrupt+0x52/0xd0 arch/x86/kernel/irq.c:247
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:640
RIP: 0010:__do_softirq+0x1e0/0x8de kernel/softirq.c:539
Code: 89 44 24 18 44 88 74 24 3b 48 c7 c7 00 55 cb 8a e8 65 51 fc ff 65 66 c7 05 4b ca 71 75 00 00 e8 a6 0c fd f6 fb bb ff ff ff ff <49> c7 c6 c0 a0 e0 8c 41 0f bc dc 83 c3 01 0f 85 a2 00 00 00 e9 6b
RSP: 0018:ffffc90000007f30 EFLAGS: 00000206
RAX: 0000000000154418 RBX: 00000000ffffffff RCX: 1ffffffff1e758b1
RDX: 0000000000000000 RSI: ffffffff8accae80 RDI: ffffffff8b2fd380
RBP: 000000010000150c R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8f3af817 R11: 0000000000000000 R12: 0000000000000282
R13: 000000000000000a R14: 0000000000000001 R15: 0000000000000000
 invoke_softirq kernel/softirq.c:427 [inline]
 __irq_exit_rcu kernel/softirq.c:632 [inline]
 irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline]
RIP: 0010:default_idle+0xf/0x20 arch/x86/kernel/process.c:743
Code: 89 07 49 c7 c0 08 00 00 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 76 ff ff ff cc cc cc cc f3 0f 1e fa 66 90 0f 00 2d 43 53 38 00 fb f4 <fa> c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 65
RSP: 0018:ffffffff8ce07e18 EFLAGS: 00000242
RAX: 0000000000154413 RBX: 0000000000000000 RCX: ffffffff8a8e41e7
RDX: 0000000000000000 RSI: ffffffff8accae80 RDI: ffffffff8b2fd380
RBP: fffffbfff19d2b48 R08: 0000000000000001 R09: ffffed10058c6ded
R10: ffff88802c636f6b R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8ce95a40 R14: ffffffff8f3af810 R15: 0000000000000000
 default_idle_call+0x69/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x332/0x400 kernel/sched/idle.c:312
 cpu_startup_entry+0x50/0x60 kernel/sched/idle.c:410
 rest_init+0x16f/0x2b0 init/main.c:730
 arch_call_rest_init+0x13/0x30 init/main.c:827
 start_kernel+0x39f/0x480 init/main.c:1072
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:555
 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:536
 secondary_startup_64_no_verify+0x170/0x17b
 </TASK>
----------------
Code disassembly (best guess):
   0:	89 44 24 18          	mov    %eax,0x18(%rsp)
   4:	44 88 74 24 3b       	mov    %r14b,0x3b(%rsp)
   9:	48 c7 c7 00 55 cb 8a 	mov    $0xffffffff8acb5500,%rdi
  10:	e8 65 51 fc ff       	call   0xfffc517a
  15:	65 66 c7 05 4b ca 71 	movw   $0x0,%gs:0x7571ca4b(%rip)        # 0x7571ca6a
  1c:	75 00 00
  1f:	e8 a6 0c fd f6       	call   0xf6fd0cca
  24:	fb                   	sti
  25:	bb ff ff ff ff       	mov    $0xffffffff,%ebx
* 2a:	49 c7 c6 c0 a0 e0 8c 	mov    $0xffffffff8ce0a0c0,%r14 <-- trapping instruction
  31:	41 0f bc dc          	bsf    %r12d,%ebx
  35:	83 c3 01             	add    $0x1,%ebx
  38:	0f 85 a2 00 00 00    	jne    0xe0
  3e:	e9                   	.byte 0xe9
  3f:	6b                   	.byte 0x6b