Re: [syzbot] [cifs?] WARNING in smb2_add_credits

Re: [syzbot] [cifs?] WARNING in smb2_add_credits

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    848acc8ffe1b Merge tag 'fsverity-for-linus' of git://git.k..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13947e32580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=eeb58d2197d88720a228
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=174b13b9580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10f47649580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/32c9dc084aaa/disk-848acc8f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b7604244b0a9/vmlinux-848acc8f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4cd321f6fe47/bzImage-848acc8f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eeb58d2197d88720a228@syzkaller.appspotmail.com

CIFS: VFS: \\127.0.0.1 Error -32 sending data on socket to server
------------[ cut here ]------------
server->in_flight == 0
WARNING: fs/smb/client/smb2ops.c:104 at smb2_add_credits+0x1213/0x1790 fs/smb/client/smb2ops.c:104, CPU#0: syz-executor203/8920
Modules linked in:
CPU: 0 UID: 0 PID: 8920 Comm: syz-executor203 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:smb2_add_credits+0x1213/0x1790 fs/smb/client/smb2ops.c:104
Code: c6 e8 d1 e9 b5 fe 84 db 0f 85 0a fb ff ff e8 b4 ef b5 fe 48 8d 3d 9d ad d5 0d 67 48 0f b9 3a e9 f4 fa ff ff e8 9e ef b5 fe 90 <0f> 0b 90 0f b6 05 9c e3 b5 0d 31 ff 89 c6 88 44 24 28 e8 96 e9 b5
RSP: 0018:ffffc90008187208 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888032dce300 RCX: ffffffff835465cb
RDX: ffff88802c5d8000 RSI: ffffffff83547542 RDI: ffff88802c5d8000
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90008187448
R13: 0000000000000200 R14: 0000000000000001 R15: ffff888032dce000
FS:  00007f73289316c0(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f73289d463c CR3: 0000000071a37000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 add_credits fs/smb/client/cifsglob.h:894 [inline]
 compound_send_recv+0x1030/0x2a10 fs/smb/client/transport.c:979
 cifs_send_recv+0x43/0x60 fs/smb/client/transport.c:1106
 SMB2_negotiate+0x15c4/0x5380 fs/smb/client/smb2pdu.c:1188
 cifs_negotiate_protocol fs/smb/client/connect.c:4043 [inline]
 cifs_negotiate_protocol+0x268/0x4c0 fs/smb/client/connect.c:4014
 cifs_get_smb_ses+0xfc9/0x2170 fs/smb/client/connect.c:2492
 cifs_mount_get_session+0xf8/0x460 fs/smb/client/connect.c:3578
 get_session fs/smb/client/dfs.c:65 [inline]
 dfs_mount_share+0x200/0x1e20 fs/smb/client/dfs.c:275
 cifs_mount+0xc4/0xdb0 fs/smb/client/connect.c:3860
 cifs_smb3_do_mount+0x2c0/0x1b20 fs/smb/client/cifsfs.c:1024
 smb3_get_tree_common fs/smb/client/fs_context.c:897 [inline]
 smb3_get_tree fs/smb/client/fs_context.c:917 [inline]
 smb3_get_tree+0x1fd/0x440 fs/smb/client/fs_context.c:909
 vfs_get_tree+0x92/0x320 fs/super.c:1700
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount fs/namespace.c:3841 [inline]
 path_mount+0x7d0/0x23d0 fs/namespace.c:4161
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount fs/namespace.c:4367 [inline]
 __x64_sys_mount+0x293/0x310 fs/namespace.c:4367
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7328959099
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f73289311d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f7328a09b48 RCX: 00007f7328959099
RDX: 0000200000000400 RSI: 0000200000000300 RDI: 0000200000000200
RBP: 00007f7328a09b40 R08: 0000200000000500 R09: 38203a6b63617473
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f73289db378
R13: 0000200000000200 R14: 0000200000000400 R15: 0000200000000300
 </TASK>


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