Subject: [syzbot] [hams?] WARNING: ODEBUG bug in rose_release

From: syzbot <[email-masked]>
Date: Thu, 23 Apr 2026 06:23:32 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    2a4c0c11c019 Merge tag 's390-7.1-1' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12df3702580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3e19fa1907a3dfda
dashboard link: https://syzkaller.appspot.com/bug?extid=b091c5774423d1319a22
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-2a4c0c11.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2702dddfd186/vmlinux-2a4c0c11.xz
kernel image: https://storage.googleapis.com/syzbot-assets/51878be8732c/bzImage-2a4c0c11.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff88803f4d2090 object type: timer_list hint: rose_t0timer_expiry+0x0/0x150 include/linux/skbuff.h:2942
WARNING: lib/debugobjects.c:629 at debug_print_object+0x18e/0x2a0 lib/debugobjects.c:629, CPU#2: syz.1.11287/7248
Modules linked in:
CPU: 2 UID: 0 PID: 7248 Comm: syz.1.11287 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:debug_print_object+0x19b/0x2a0 lib/debugobjects.c:629
Code: b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4f 48 8d 3d f2 18 e4 0b 41 56 48 8b 14 dd c0 33 1c 8c 4c 89 e6 <67> 48 0f b9 3a 58 83 05 0c c5 d9 0b 01 48 83 c4 18 5b 5d 41 5c 41
RSP: 0018:ffffc90005ba7808 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: ffffffff8c1c3300 RSI: ffffffff8c1c2f20 RDI: ffffffff90e6aac0
RBP: 0000000000000001 R08: ffff88803f4d2090 R09: ffffffff8bb2c6e0
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8c1c2f20
R13: ffffffff8bb2c720 R14: ffffffff8a84b230 R15: ffffc90005ba7908
FS:  0000000000000000(0000) GS:ffff8880d64db000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555594c2f9e8 CR3: 0000000039419000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __debug_check_no_obj_freed lib/debugobjects.c:1116 [inline]
 debug_check_no_obj_freed+0x4da/0x630 lib/debugobjects.c:1146
 slab_free_hook mm/slub.c:2620 [inline]
 slab_free mm/slub.c:6246 [inline]
 kfree+0x3d0/0x6c0 mm/slub.c:6561
 rose_neigh_put include/net/rose.h:166 [inline]
 rose_neigh_put include/net/rose.h:160 [inline]
 rose_release+0x60b/0x740 net/rose/af_rose.c:658
 __sock_release+0xb3/0x260 net/socket.c:722
 sock_close+0x1c/0x30 net/socket.c:1514
 __fput+0x3ff/0xb50 fs/file_table.c:510
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8d2/0x2a60 kernel/exit.c:975
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1117
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3037
 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x706/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: eccb:0xe4a421182f13d611
Code: Unable to access opcode bytes at 0xe4a421182f13d5e7.
RSP: 002b:00007fb92f11ff58 EFLAGS: 00000756 ORIG_RAX: d1d66dbfed01019b
RAX: 2bf9e1987c1988ee RBX: 6f67a894836fe1f3 RCX: ed0b474b2b46640f
RDX: fb381f0b5e12d2ce RSI: 401aaa756d8c34aa RDI: 30b9ec15aecde911
RBP: 532828f82bbb556c R08: dbce39d105fdbf88 R09: ae9ea378b9c9fbc7
R10: 33740f3b8630618c R11: 2450ade207355af5 R12: 0a61688f027fb1a4
R13: 339c71c774e61334 R14: 28baed4a0483d193 R15: 7c1f9cf2b758efdc
 </TASK>
----------------
Code disassembly (best guess):
   0:	b8 00 00 00 00       	mov    $0x0,%eax
   5:	00 fc                	add    %bh,%ah
   7:	ff                   	lcall  (bad)
   8:	df 48 89             	fisttps -0x77(%rax)
   b:	fa                   	cli
   c:	48 c1 ea 03          	shr    $0x3,%rdx
  10:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
  14:	75 4f                	jne    0x65
  16:	48 8d 3d f2 18 e4 0b 	lea    0xbe418f2(%rip),%rdi        # 0xbe4190f
  1d:	41 56                	push   %r14
  1f:	48 8b 14 dd c0 33 1c 	mov    -0x73e3cc40(,%rbx,8),%rdx
  26:	8c
  27:	4c 89 e6             	mov    %r12,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	58                   	pop    %rax
  30:	83 05 0c c5 d9 0b 01 	addl   $0x1,0xbd9c50c(%rip)        # 0xbd9c543
  37:	48 83 c4 18          	add    $0x18,%rsp
  3b:	5b                   	pop    %rbx
  3c:	5d                   	pop    %rbp
  3d:	41 5c                	pop    %r12
  3f:	41                   	rex.B

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