CIFS: No dialect specified on mount. Default has changed to a more secure dialect, SMB2.1 or later (e.g. SMB3.1.1), from CIFS (SMB1). To use the less secure SMB1 dialect to access old servers which do not support SMB3.1.1 (or even SMB3 or SMB2.1) specify vers=1.0 on mount.
CIFS: Attempting to mount //127.0.0.1/share
CIFS: VFS: \\127.0.0.1 Error -512 sending data on socket to server
------------[ cut here ]------------
server->in_flight == 0
WARNING: fs/smb/client/smb2ops.c:104 at smb2_add_credits+0x1249/0x2b70 fs/smb/client/smb2ops.c:104, CPU#0: syz.0.0/5330
Modules linked in:
CPU: 0 UID: 0 PID: 5330 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:smb2_add_credits+0x1249/0x2b70 fs/smb/client/smb2ops.c:104
Code: de 83 e6 01 31 ff e8 46 83 bc fe f6 c3 01 75 0a e8 fc 7e bc fe e9 22 13 00 00 0f 1f 44 00 00 e8 ed 7e bc fe e9 13 13 00 00 90 <0f> 0b 90 80 3d 07 a3 36 0d 01 0f 85 9e 03 00 00 e8 d2 7e bc fe 49
RSP: 0018:ffffc9000f7ef318 EFLAGS: 00010246
RAX: ffffffff830a8718 RBX: 1ffff11006815c61 RCX: 0000000000000002
RDX: ffff888012f82540 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000200 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff830ab470 R12: ffff8880340ae308
R13: ffffc9000f7ef530 R14: ffff8880340ae000 R15: 0000000000000000
FS:  00007f790a26e6c0(0000) GS:ffff88808c543000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b94e8e3168 CR3: 0000000042fad000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 add_credits fs/smb/client/cifsglob.h:894 [inline]
 compound_send_recv+0x13b4/0x2b90 fs/smb/client/transport.c:979
 cifs_send_recv+0x42/0x60 fs/smb/client/transport.c:1106
 SMB2_negotiate+0x164d/0x4030 fs/smb/client/smb2pdu.c:1188
 cifs_negotiate_protocol+0x45d/0x680 fs/smb/client/connect.c:4043
 cifs_get_smb_ses+0x1104/0x1ff0 fs/smb/client/connect.c:2492
 cifs_mount_get_session+0xf1/0x450 fs/smb/client/connect.c:3578
 get_session fs/smb/client/dfs.c:65 [inline]
 dfs_mount_share+0x22e/0x990 fs/smb/client/dfs.c:275
 cifs_mount+0xcc/0xbf0 fs/smb/client/connect.c:3860
 cifs_smb3_do_mount+0x2d0/0x8a0 fs/smb/client/cifsfs.c:1024
 smb3_get_tree_common fs/smb/client/fs_context.c:897 [inline]
 smb3_get_tree+0x2dd/0x400 fs/smb/client/fs_context.c:917
 vfs_get_tree+0x92/0x2a0 fs/super.c:1700
 vfs_cmd_create+0xa2/0x200 fs/fsopen.c:231
 __do_sys_fsconfig fs/fsopen.c:463 [inline]
 __se_sys_fsconfig+0x6b9/0x810 fs/fsopen.c:350
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f790939de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f790a26dfe8 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 00007f7909625fa0 RCX: 00007f790939de99
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000007
RBP: 00007f7909433eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7909626038 R14: 00007f7909625fa0 R15: 00007ffddc7deb48
 </TASK>