syzbot


kernel BUG in sctp_getsockopt_peeloff_common

Status: fixed on 2026/01/25 17:01
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+984a5c208d87765b2ee7@syzkaller.appspotmail.com
Fix commit: afb9917d9b37 Revert "net/socket: convert sock_map_fd() to FD_ADD()"
First crash: 58d, last: 56d
Cause bisection: introduced by (bisect log) :
commit 457528eb27c3a3053181939ca65998477cc39c49
Author: Christian Brauner <brauner@kernel.org>
Date: Sun Nov 23 16:33:47 2025 +0000

  net/sctp: convert sctp_getsockopt_peeloff_common() to FD_PREPARE()

Crash: kernel BUG in sctp_getsockopt_peeloff_common (log)
Repro: C syz .config
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [fs?] kernel BUG in sctp_getsockopt_peeloff_common 6 (9) 2025/12/25 14:39
Last patch testing requests (5)
Created Duration User Patch Repo Result
2025/12/16 20:16 15m retest repro linux-next error
2025/12/16 20:16 9m retest repro linux-next error
2025/12/16 20:16 17m retest repro linux-next error
2025/12/16 20:16 10m retest repro linux-next error
2025/12/01 12:57 39m mjguzik@gmail.com patch linux-next OK log

Sample crash report:
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

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/01 07:09 linux-next 7d31f578f323 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in sctp_getsockopt_peeloff_common
2025/12/01 05:45 linux-next 7d31f578f323 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in sctp_getsockopt_peeloff_common
2025/12/01 04:21 linux-next 7d31f578f323 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in sctp_getsockopt_peeloff_common
2025/12/01 03:10 linux-next 7d31f578f323 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in sctp_getsockopt_peeloff_common
2025/12/02 17:38 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in sctp_getsockopt_peeloff_common
2025/12/01 01:58 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in sctp_getsockopt_peeloff_common
* Struck through repros no longer work on HEAD.