From: syzbot <syzbot+681e729b2cf0d4860042@syzkaller.appspotmail.com>
To: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
luto@kernel.org, mingo@redhat.com, nogikh@google.com,
peterz@infradead.org, syzkaller-bugs@googlegroups.com,
tglx@kernel.org, x86@kernel.org
Subject: Re: [syzbot] [mm?] WARNING in update_rq_clock (2)
Date: Sun, 02 Aug 2026 23:40:33 -0700 [thread overview]
Message-ID: <6a7037e1.2d659fcc.1d46f5.01e6.GAE@google.com> (raw)
In-Reply-To: <6a470486.52c20a74.1f8b39.000c.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: cc2b5f627e8c Add linux-next specific files for 20260714
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=17122649580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=681e729b2cf0d4860042
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=11908cc6580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1042ec9e580000
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+681e729b2cf0d4860042@syzkaller.appspotmail.com
------------[ cut here ]------------
debug_locks && !(lock_is_held(&(__rq_lockp(rq))->dep_map) != 0)
WARNING: kernel/sched/sched.h:1652 at lockdep_assert_rq_held kernel/sched/sched.h:1652 [inline], CPU#0: syz-executor108/5647
WARNING: kernel/sched/sched.h:1652 at update_rq_clock+0x34d/0x560 kernel/sched/core.c:865, CPU#0: syz-executor108/5647
Modules linked in:
CPU: 0 UID: 0 PID: 5647 Comm: syz-executor108 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1652 [inline]
RIP: 0010:update_rq_clock+0x34d/0x560 kernel/sched/core.c:865
Code: 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 8b f0 9d 00 4c 01 3b 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d e9 85 e6 bf 09 cc 90 <0f> 0b 90 e9 42 fd ff ff 48 89 df 48 83 c4 10 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90004e9f618 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b873b880 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8dbfaa0e RDI: ffffffff8bcbd080
RBP: dffffc0000000000 R08: ffffffff8fd0c47f R09: 1ffffffff1fa188f
R10: dffffc0000000000 R11: ffffffff819e4d80 R12: 0000000000000001
R13: dffffc0000000001 R14: ffff8880b873c748 R15: ffff8880b873b880
FS: 00007fb5334a16c0(0000) GS:ffff8881259f2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb5334a0ff8 CR3: 0000000034948000 CR4: 00000000003526f0
Call Trace:
<TASK>
pick_next_task kernel/sched/core.c:6335 [inline]
__schedule+0x3774/0x5530 kernel/sched/core.c:7146
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7553
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__outb arch/x86/include/asm/shared/io.h:22 [inline]
RIP: 0010:rtc_cmos_write+0x13/0x20 arch/x86/kernel/rtc.c:97
Code: 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 53 89 f3 89 fd e8 51 9f 59 00 89 d8 e6 70 <89> e8 e6 71 5b 5d c3 cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90004e9f970 EFLAGS: 00000293
RAX: 000000000000000f RBX: 000000000000000f RCX: ffff8880350e3e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e3c3880 R12: ffffffff8dc427d8
R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff8880b8723f90
smpboot_restore_warm_reset_vector arch/x86/kernel/smpboot.c:162 [inline]
arch_cpuhp_cleanup_kick_cpu+0xbf/0x150 arch/x86/kernel/smpboot.c:1129
cpuhp_bp_sync_alive kernel/cpu.c:449 [inline]
cpuhp_bringup_ap+0x90/0x360 kernel/cpu.c:843
cpuhp_invoke_callback+0x434/0x810 kernel/cpu.c:194
__cpuhp_invoke_callback_range kernel/cpu.c:972 [inline]
cpuhp_invoke_callback_range kernel/cpu.c:996 [inline]
cpuhp_up_callbacks kernel/cpu.c:1027 [inline]
_cpu_up+0x2ce/0x5b0 kernel/cpu.c:1674
cpu_up+0x1d2/0x220 kernel/cpu.c:1706
cpu_subsys_online+0x67/0x280 drivers/base/cpu.c:61
device_online+0x181/0x1e0 drivers/base/core.c:4308
online_store+0xd7/0x1a0 drivers/base/core.c:2879
kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61e/0xbb0 fs/read_write.c:687
ksys_write+0x156/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb5334ea0a9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb5334a11d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb53359ab58 RCX: 00007fb5334ea0a9
RDX: 0000000000000001 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007fb53359ab50 R08: 00007fb5334a16c0 R09: 35203a6b63617473
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb53356c378
R13: 0000200000000100 R14: 0000200000000140 R15: 0000200000000180
</TASK>
----------------
Code disassembly (best guess):
0: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: f3 0f 1e fa endbr64
1b: 55 push %rbp
1c: 53 push %rbx
1d: 89 f3 mov %esi,%ebx
1f: 89 fd mov %edi,%ebp
21: e8 51 9f 59 00 call 0x599f77
26: 89 d8 mov %ebx,%eax
28: e6 70 out %al,$0x70
* 2a: 89 e8 mov %ebp,%eax <-- trapping instruction
2c: e6 71 out %al,$0x71
2e: 5b pop %rbx
2f: 5d pop %rbp
30: c3 ret
31: cc int3
32: cc int3
33: cc int3
34: cc int3
35: cc int3
36: 90 nop
37: 90 nop
38: 90 nop
39: 90 nop
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
parent reply other threads:[~2026-08-03 6:40 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <6a470486.52c20a74.1f8b39.000c.GAE@google.com>]
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