syzbot
WARNING: ODEBUG bug in mcheck_cpu_init
Status:
moderation: reported on 2026/10/09 13:58
Subsystems:
edac
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+fcc0b3f9f99f26c710d7@syzkaller.appspotmail.com
First crash: 4d02h, last: 4d02h
Sample crash report:
------------[ cut here ]------------
ODEBUG: init active (active state 0) object: ffff88802b523440 object type: timer_list hint: mce_timer_fn+0x0/0x2e0 arch/x86/kernel/cpu/mce/core.c:2717
WARNING: lib/debugobjects.c:629 at debug_print_object+0x198/0x2b0 lib/debugobjects.c:629, CPU#3: swapper/3/0
Modules linked in:
CPU: 3 UID: 0 PID: 0 Comm: swapper/3 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:debug_print_object+0x1a5/0x2b0 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 d8 b1 1c 0c 41 56 48 8b 14 ed 40 52 62 8c 4c 89 e6 <67> 48 0f b9 3a 58 83 05 e2 e1 11 0c 01 48 83 c4 18 5b 5d 41 5c 41
RSP: 0000:ffffc9000049fc78 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffffc9000049fd20 RCX: 0000000000000000
RDX: ffffffff8c625180 RSI: ffffffff8c624ce0 RDI: ffffffff91508dd0
RBP: 0000000000000003 R08: ffff88802b523440 R09: ffffffff8bf31240
R10: ffffffff9bc2e87b R11: 0000000000000000 R12: ffffffff8c624ce0
R13: ffffffff8bf31280 R14: ffffffff81b2b0a0 R15: ffffc9000049fd38
FS: 0000000000000000(0000) GS:ffff888096c52000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000eb96000 CR4: 0000000000350eb0
Call Trace:
<TASK>
__debug_object_init+0x229/0x3d0 lib/debugobjects.c:818
debug_timer_init kernel/time/timer.c:788 [inline]
debug_init kernel/time/timer.c:836 [inline]
timer_init_key+0x35/0x310 kernel/time/timer.c:880
__mcheck_cpu_setup_timer arch/x86/kernel/cpu/mce/core.c:2087 [inline]
mcheck_cpu_init+0x273/0x4d0 arch/x86/kernel/cpu/mce/core.c:2262
identify_cpu+0xe84/0x1c40 arch/x86/kernel/cpu/common.c:2126
identify_secondary_cpu+0x178/0x270 arch/x86/kernel/cpu/common.c:2187
ap_starting arch/x86/kernel/smpboot.c:190 [inline]
start_secondary+0xcf/0x2d0 arch/x86/kernel/smpboot.c:280
common_startup_64+0x13e/0x158
</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 d8 b1 1c 0c lea 0xc1cb1d8(%rip),%rdi # 0xc1cb1f5
1d: 41 56 push %r14
1f: 48 8b 14 ed 40 52 62 mov -0x739dadc0(,%rbp,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 e2 e1 11 0c 01 addl $0x1,0xc11e1e2(%rip) # 0xc11e219
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
* Struck through repros no longer work on HEAD.