[syzbot] [fs?] kernel BUG in sctp_getsockopt_peeloff_common

[syzbot <syzbot+984a5c208d87765b2ee7@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    7d31f578f323 Add linux-next specific files for 20251128
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=156402b4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6336d8e94a7c517d
dashboard link: https://syzkaller.appspot.com/bug?extid=984a5c208d87765b2ee7
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16a2322c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12a3c512580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6b49d8ad90de/disk-7d31f578.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dbe2d4988ca7/vmlinux-7d31f578.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0448ab2411/bzImage-7d31f578.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+984a5c208d87765b2ee7@syzkaller.appspotmail.com

R10: 0000200000000340 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f49009e5fa0 R14: 00007f49009e5fa0 R15: 0000000000000005
 </TASK>
VFS_BUG_ON_INODE(inode_state_read_once(inode) & I_CLEAR) encountered for inode ffff88805d116e00
fs sockfs mode 140777 opflags 0xc flags 0x0 state 0x300 count 0
------------[ cut here ]------------
kernel BUG at fs/inode.c:1971!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 5997 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:iput+0xfc9/0x1030 fs/inode.c:1971
Code: 8b 7c 24 18 48 c7 c6 e0 f2 79 8b e8 51 f8 e6 fe 90 0f 0b e8 a9 6f 80 ff 48 8b 7c 24 18 48 c7 c6 80 f2 79 8b e8 38 f8 e6 fe 90 <0f> 0b 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c cd fb ff ff 4c 89 ef
RSP: 0018:ffffc90003987b18 EFLAGS: 00010282
RAX: 000000000000009f RBX: dffffc0000000000 RCX: e99d72d115a78d00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffffffff1ed7c72 R08: ffffc900039877c7 R09: 1ffff92000730ef8
R10: dffffc0000000000 R11: fffff52000730ef9 R12: 1ffff1100ba22e00
R13: ffff88805d117000 R14: 0000000000000200 R15: 1ffffffff1f02c74
FS:  000055557d588500(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000200 CR3: 0000000074b6e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 sctp_getsockopt_peeloff_common+0x6b7/0x8a0 net/sctp/socket.c:5733
 sctp_getsockopt_peeloff_flags+0x102/0x140 net/sctp/socket.c:5779
 sctp_getsockopt+0x3a5/0xb90 net/sctp/socket.c:8111
 do_sock_getsockopt+0x2b4/0x3d0 net/socket.c:2389
 __sys_getsockopt net/socket.c:2418 [inline]
 __do_sys_getsockopt net/socket.c:2425 [inline]
 __se_sys_getsockopt net/socket.c:2422 [inline]
 __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2422
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f490078f749
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:00007ffed38d1688 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007f49009e5fa0 RCX: 00007f490078f749
RDX: 000000000000007a RSI: 0000000000000084 RDI: 0000000000000003
RBP: 00007ffed38d16e0 R08: 0000200000000040 R09: 0000000000000000
R10: 0000200000000340 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f49009e5fa0 R14: 00007f49009e5fa0 R15: 0000000000000005
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:iput+0xfc9/0x1030 fs/inode.c:1971
Code: 8b 7c 24 18 48 c7 c6 e0 f2 79 8b e8 51 f8 e6 fe 90 0f 0b e8 a9 6f 80 ff 48 8b 7c 24 18 48 c7 c6 80 f2 79 8b e8 38 f8 e6 fe 90 <0f> 0b 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c cd fb ff ff 4c 89 ef
RSP: 0018:ffffc90003987b18 EFLAGS: 00010282
RAX: 000000000000009f RBX: dffffc0000000000 RCX: e99d72d115a78d00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffffffff1ed7c72 R08: ffffc900039877c7 R09: 1ffff92000730ef8
R10: dffffc0000000000 R11: fffff52000730ef9 R12: 1ffff1100ba22e00
R13: ffff88805d117000 R14: 0000000000000200 R15: 1ffffffff1f02c74
FS:  000055557d588500(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000200 CR3: 0000000074b6e000 CR4: 00000000003526f0


---
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