9p: Unknown Cache mode loowe
9pnet: Tag 65535 still in use
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 11707 at lib/refcount.c:28 refcount_warn_saturate+0x107/0x1f0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 11707 Comm: syz-executor.3 Not tainted 6.3.0-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:refcount_warn_saturate+0x107/0x1f0 lib/refcount.c:28
Code: 1d 41 dc 51 0a 31 ff 89 de e8 65 ea 72 fd 84 db 75 a3 e8 4c ee 72 fd 48 c7 c7 20 6a a6 8a c6 05 21 dc 51 0a 01 e8 79 5e 3b fd <0f> 0b eb 87 e8 30 ee 72 fd 0f b6 1d 0a dc 51 0a 31 ff 89 de e8 30
RSP: 0018:ffffc9002168f9d0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90024dcf000
RDX: 0000000000040000 RSI: ffffffff814b6247 RDI: 0000000000000001
RBP: ffff88804ad7fdc8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88804ad7fdc8 R14: ffff8880160e8400 R15: 1ffff920042d1f44
FS:  0000000000000000(0000) GS:ffff88802c600000(0063) knlGS:00000000f7faeb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000031127000 CR3: 000000006eea5000 CR4: 0000000000150ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:283 [inline]
 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
 refcount_dec_and_test include/linux/refcount.h:333 [inline]
 p9_req_put+0x1f6/0x250 net/9p/client.c:401
 p9_tag_cleanup net/9p/client.c:428 [inline]
 p9_client_destroy+0x214/0x470 net/9p/client.c:1072
 v9fs_session_init+0x10a8/0x1900 fs/9p/v9fs.c:487
 v9fs_mount+0xbe/0xca0 fs/9p/vfs_super.c:125
 legacy_get_tree+0x109/0x220 fs/fs_context.c:610
 vfs_get_tree+0x8d/0x350 fs/super.c:1510
 do_new_mount fs/namespace.c:3042 [inline]
 path_mount+0x1342/0x1e40 fs/namespace.c:3372
 do_mount fs/namespace.c:3385 [inline]
 __do_sys_mount fs/namespace.c:3594 [inline]
 __se_sys_mount fs/namespace.c:3571 [inline]
 __ia32_sys_mount+0x282/0x300 fs/namespace.c:3571
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82
RIP: 0023:0xf7fb3579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7fae5cc EFLAGS: 00000296 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 00000000200000c0 RCX: 0000000020000180
RDX: 00000000200001c0 RSI: 0000000000000000 RDI: 0000000020000680
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	retq
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi