[syzbot] [edac?] WARNING in mce_timer_fn

[syzbot] [edac?] WARNING in mce_timer_fn

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    cc2b5f627e8c Add linux-next specific files for 20260714
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1304e249580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=9d17de59c48d71bd6824
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14efd632580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6836f8efb1da/disk-cc2b5f62.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0109d3477cc7/vmlinux-cc2b5f62.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c2e49e350bbf/bzImage-cc2b5f62.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9d17de59c48d71bd6824@syzkaller.appspotmail.com

------------[ cut here ]------------
cpu_t != t
WARNING: arch/x86/kernel/cpu/mce/core.c:1770 at mce_timer_fn+0x23f/0x280 arch/x86/kernel/cpu/mce/core.c:1770, CPU#0: ktimers/0/16
Modules linked in:
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:mce_timer_fn+0x23f/0x280 arch/x86/kernel/cpu/mce/core.c:1770
Code: 00 75 0a e8 93 3b 55 00 e9 16 ff ff ff e8 89 3b 55 00 4c 8b 1d f2 b1 af 0c 2e 2e 2e 41 ff d3 e9 ff fe ff ff e8 72 3b 55 00 90 <0f> 0b 90 e9 33 fe ff ff e8 64 3b 55 00 48 c7 c7 a0 20 20 8e 4c 89
RSP: 0018:ffffc90000157a08 EFLAGS: 00010246
RAX: ffffffff8170683e RBX: ffff8880b87234a0 RCX: ffff88801daf8000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000100
R10: dffffc0000000000 R11: ffffffff81706600 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8dc427d0 R15: ffff8880b87234a0
FS:  0000000000000000(0000) GS:ffff8881259f2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08d99b56c8 CR3: 000000003fe3e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x67b/0x9b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0x67/0x170 kernel/time/timer.c:2403
 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1155
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
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Re: [syzbot] [edac?] WARNING in mce_timer_fn

[Borislav Petkov]

On Fri, Jul 31, 2026 at 10:16:43AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    cc2b5f627e8c Add linux-next specific files for 20260714

$ git checkout cc2b5f627e8c
error: pathspec 'cc2b5f627e8c' did not match any file(s) known to git

Looks like a report from 2 weeks ago.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [syzbot] [edac?] WARNING in mce_timer_fn

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    70dd4ee72eb2 Merge tag 'pinctrl-v7.3-3' of git://git.kerne..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=114c8031580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=129d675874dbf896
dashboard link: https://syzkaller.appspot.com/bug?extid=9d17de59c48d71bd6824
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1391efd1580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9d17de59c48d71bd6824@syzkaller.appspotmail.com

------------[ cut here ]------------
cpu_t != t
WARNING: arch/x86/kernel/cpu/mce/core.c:1770 at mce_timer_fn+0x289/0x2e0 arch/x86/kernel/cpu/mce/core.c:1770, CPU#0: udevd/4970
Modules linked in:
CPU: 0 UID: 0 PID: 4970 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
RIP: 0010:mce_timer_fn+0x289/0x2e0 arch/x86/kernel/cpu/mce/core.c:1770
Code: 59 00 4d 01 e4 4d 39 ec 4d 0f 47 e5 31 ff 4c 89 e6 e8 6b 40 59 00 4d 85 e4 0f 84 20 ff ff ff e9 f7 fe ff ff e8 b8 45 59 00 90 <0f> 0b 90 e9 cf fd ff ff 4c 89 f6 48 c7 c7 a0 ef bf 8f e8 60 dc 84
RSP: 0018:ffffc90000007c20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880b8223440 RCX: 0000000000000100
RDX: ffff88807cbccb00 RSI: ffffffff81b311b8 RDI: ffffffff8e6af920
RBP: ffff8880b8323440 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000100 R14: 1ffff92000000f8d R15: ffffffff81b30f30
FS:  00007fa1f48b4880(0000) GS:ffff888122946000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563a7ab14be0 CR3: 000000007be29000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 call_timer_fn+0x198/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x10/0x50 kernel/time/timer.c:2403
 handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0x16a/0x210 kernel/softirq.c:758
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5938 [inline]
RIP: 0010:lock_acquire+0x166/0x380 kernel/locking/lockdep.c:5899
Code: d5 00 00 00 65 8b 05 61 63 a6 13 85 c0 0f 85 c6 00 00 00 65 48 8b 05 91 1c a6 13 8b 90 a4 0b 00 00 85 d2 0f 85 b0 00 00 00 9c <8f> 04 24 fa 48 c7 c7 49 a7 4d 8e e8 6a 07 ed 09 45 89 e8 44 89 f6
RSP: 0018:ffffc90004e9f578 EFLAGS: 00000246
RAX: ffff88807cbccb00 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff81b9c261 RDI: fffffbfff1fbd8bc
RBP: ffffffff8fdec5e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000200 R11: 000000000000b9e5 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
 __unwind_start+0x3cd/0x7e0 arch/x86/kernel/unwind_orc.c:787
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5414 [inline]
 __kmalloc_noprof+0x32f/0x840 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x276/0x460 security/tomoyo/file.c:827
 security_inode_getattr+0x116/0x280 security/security.c:1895
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat+0x4b/0xe0 fs/stat.c:281
 __do_sys_newfstat+0x8b/0x110 fs/stat.c:551
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa1f4111ad7
Code: 73 01 c3 48 8b 0d 21 f3 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 05 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8
RSP: 002b:00007ffe5cd40ab8 EFLAGS: 00000206 ORIG_RAX: 0000000000000005
RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007fa1f4111ad7
RDX: 0000000000090800 RSI: 00007ffe5cd40ac0 RDI: 000000000000000d
RBP: 00007ffe5cd40ac0 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 00005592845d9170
R13: 00000000000000ff R14: 000055926871bbe0 R15: 00007ffe5cd40e10
 </TASK>
----------------
Code disassembly (best guess):
   0:	d5 00 00 00          	{rex2 0x0} add %al,(%rax)
   4:	65 8b 05 61 63 a6 13 	mov    %gs:0x13a66361(%rip),%eax        # 0x13a6636c
   b:	85 c0                	test   %eax,%eax
   d:	0f 85 c6 00 00 00    	jne    0xd9
  13:	65 48 8b 05 91 1c a6 	mov    %gs:0x13a61c91(%rip),%rax        # 0x13a61cac
  1a:	13
  1b:	8b 90 a4 0b 00 00    	mov    0xba4(%rax),%edx
  21:	85 d2                	test   %edx,%edx
  23:	0f 85 b0 00 00 00    	jne    0xd9
  29:	9c                   	pushf
* 2a:	8f 04 24             	pop    (%rsp) <-- trapping instruction
  2d:	fa                   	cli
  2e:	48 c7 c7 49 a7 4d 8e 	mov    $0xffffffff8e4da749,%rdi
  35:	e8 6a 07 ed 09       	call   0x9ed07a4
  3a:	45 89 e8             	mov    %r13d,%r8d
  3d:	44 89 f6             	mov    %r14d,%esi


---
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#syz test: git://repo/address.git branch-or-commit-hash
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