9p: Unknown Cache mode or invalid value fsca
9pnet: Tag 65535 still in use
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 6007 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 6007 Comm: syz.0.53 Not tainted 6.11.0-rc1-syzkaller-00046-gc91a7dee0555 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 a8 05 08 fd 84 db 0f 85 66 ff ff ff e8 fb 0a 08 fd c6 05 57 14 79 0b 01 90 48 c7 c7 80 1f b0 8b e8 97 51 ca fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 d8 0a 08 fd 0f b6 1d 32 14 79 0b 31
RSP: 0018:ffffc900036c79d0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90003a91000
RDX: 0000000000040000 RSI: ffffffff814cc386 RDI: 0000000000000001
RBP: ffff88802acc4008 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffc900036c7a68
R13: ffff88802acc4008 R14: ffff888016775c00 R15: 1ffff920006d8f45
FS:  00007f1079c6e6c0(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f10789ffd58 CR3: 000000001ecde000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:275 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 p9_req_put+0x1f4/0x250 net/9p/client.c:404
 p9_tag_cleanup net/9p/client.c:431 [inline]
 p9_client_destroy+0x22c/0x480 net/9p/client.c:1076
 v9fs_session_init+0xba3/0x1a80 fs/9p/v9fs.c:490
 v9fs_mount+0xc6/0xaa0 fs/9p/vfs_super.c:122
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1800
 do_new_mount fs/namespace.c:3472 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3799
 do_mount fs/namespace.c:3812 [inline]
 __do_sys_mount fs/namespace.c:4020 [inline]
 __se_sys_mount fs/namespace.c:3997 [inline]
 __x64_sys_mount+0x294/0x320 fs/namespace.c:3997
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1078f773b9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1079c6e048 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1079105f80 RCX: 00007f1078f773b9
RDX: 00000000200004c0 RSI: 0000000020000480 RDI: 00000000200001c0
RBP: 00007f1078fe48e6 R08: 0000000020000840 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f1079105f80 R15: 00007fff7112f508
 </TASK>