From: syzbot <syzbot+eb74dca0d1eb3ec227a7@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
mathieu.desnoyers@efficios.com, mhiramat@kernel.org,
rostedt@goodmis.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [trace?] WARNING in check_buffer
Date: Sun, 20 Sep 2026 07:21:32 -0700 [thread overview]
Message-ID: <6aafebec.a6af0033.177e91.000d.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: 40288c9206c1 Merge tag 'drm-fixes-2026-09-19' of https://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12daa525580000
kernel config: https://syzkaller.appspot.com/x/.config?x=84649d3ff8d550cb
dashboard link: https://syzkaller.appspot.com/bug?extid=eb74dca0d1eb3ec227a7
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: https://storage.googleapis.com/syzbot-assets/96e6db480769/disk-40288c92.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d8cb5ded77e9/vmlinux-40288c92.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c127cac2df37/bzImage-40288c92.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eb74dca0d1eb3ec227a7@syzkaller.appspotmail.com
0xe74: [135187] delta:1 PADDING
0xe98: [135188] delta:1 hd
expected end:0xea8 last event actually ended at:0xea8
------------[ cut here ]------------
system_state != SYSTEM_BOOTING
WARNING: kernel/trace/ring_buffer.c:4783 at check_buffer.cold+0x1a2/0x1ef kernel/trace/ring_buffer.c:4783, CPU#0: syz.6.3124/18331
Modules linked in:
CPU: 0 UID: 0 PID: 18331 Comm: syz.6.3124 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
RIP: 0010:check_buffer.cold+0x1a2/0x1ef kernel/trace/ring_buffer.c:4783
Code: 03 0f b6 14 11 38 d0 7c 04 84 d2 75 5c 8b 2d 1c ce 21 10 31 ff 89 ee e8 af f2 e8 00 85 ed 0f 84 c8 8d eb 00 e8 32 f8 e8 00 90 <0f> 0b 90 e9 73 8b eb 00 49 c7 c7 c0 5e f6 8b e9 51 fe ff ff e8 88
RSP: 0018:ffffc900000078d0 EFLAGS: 00010046
RAX: 8000000001000003 RBX: 1ffff92000000f20 RCX: 0000000001000003
RDX: ffff88802d9c4b00 RSI: ffffffff8123277e RDI: ffff88802d9c4b00
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000021015
R13: ffff88801c095000 R14: ffff88805713c000 R15: ffffffff8bf65a60
FS: 00007ff5dabbc6c0(0000) GS:ffff888123b56000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32508ff8 CR3: 0000000084816000 CR4: 00000000003526f0
Call Trace:
<IRQ>
__rb_reserve_next.constprop.0+0x486/0x1640 kernel/trace/ring_buffer.c:4873
rb_reserve_next_event kernel/trace/ring_buffer.c:5010 [inline]
ring_buffer_lock_reserve+0x49a/0x1220 kernel/trace/ring_buffer.c:5069
__trace_buffer_lock_reserve kernel/trace/trace.h:1677 [inline]
trace_event_buffer_lock_reserve+0x123/0x6f0 kernel/trace/trace.c:1924
trace_event_buffer_reserve+0x1f9/0x350 kernel/trace/trace_events.c:715
__eprobe_trace_func kernel/trace/trace_eprobe.c:443 [inline]
eprobe_trigger_func+0x558/0x1450 kernel/trace/trace_eprobe.c:487
data_ops_trigger kernel/trace/trace_events_trigger.c:154 [inline]
event_triggers_call+0x29e/0x4d0 kernel/trace/trace_events_trigger.c:209
__event_trigger_test_discard kernel/trace/trace.h:1738 [inline]
trace_event_buffer_commit+0x66b/0xa80 kernel/trace/trace.c:2014
do_trace_event_raw_event_msr_trace_class arch/x86/include/asm/msr-trace.h:21 [inline]
trace_event_raw_event_msr_trace_class+0x17d/0x270 arch/x86/include/asm/msr-trace.h:21
__do_trace_read_msr arch/x86/include/asm/msr-trace.h:40 [inline]
trace_read_msr+0x160/0x1f0 arch/x86/include/asm/msr-trace.h:40
native_read_msr_safe arch/x86/include/asm/msr.h:127 [inline]
rdmsrq_safe arch/x86/include/asm/msr.h:220 [inline]
__rdmsr_safe_on_cpu+0xc8/0xf0 arch/x86/lib/msr-smp.c:124
csd_do_func kernel/smp.c:143 [inline]
__flush_smp_call_function_queue+0x43a/0x8c0 kernel/smp.c:632
__sysvec_call_function_single+0x81/0x420 arch/x86/kernel/smp.c:272
instr_sysvec_call_function_single arch/x86/kernel/smp.c:267 [inline]
sysvec_call_function_single+0x9e/0xc0 arch/x86/kernel/smp.c:267
</IRQ>
<TASK>
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:__vmcs_writel arch/x86/kvm/vmx/vmx_ops.h:224 [inline]
RIP: 0010:vmcs_write32 arch/x86/kvm/vmx/vmx_ops.h:242 [inline]
RIP: 0010:vmx_set_constant_host_state+0x1d4/0x740 arch/x86/kvm/vmx/vmx.c:4498
Code: e8 71 ed 6b 00 b9 74 01 00 00 0f 32 48 c1 e2 20 48 89 d3 48 09 c3 e9 ba 01 00 00 e8 56 ed 6b 00 89 db b8 00 4c 00 00 0f 79 c3 <0f> 86 f5 01 00 00 e8 41 ed 6b 00 b9 76 01 00 00 0f 32 48 c1 e2 20
RSP: 0018:ffffc90003d97828 EFLAGS: 00000202
RAX: 0000000000004c00 RBX: 0000000000000010 RCX: ffffc9000ebc9000
RDX: 0000000000080000 RSI: ffffffff81a0325a RDI: ffff88802d9c4b00
RBP: 00000000003526f0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88807e391f78
R13: ffff88807e391ed8 R14: ffff888051ff8000 R15: ffff88807e391f78
init_vmcs arch/x86/kvm/vmx/vmx.c:4946 [inline]
__vmx_vcpu_reset arch/x86/kvm/vmx/vmx.c:5014 [inline]
vmx_vcpu_reset+0x117b/0x3160 arch/x86/kvm/vmx/vmx.c:5047
kvm_vcpu_reset+0x9d1/0x1ae0 arch/x86/kvm/x86.c:9615
kvm_arch_vcpu_create+0x70c/0xab0 arch/x86/kvm/x86.c:9415
kvm_vm_ioctl_create_vcpu virt/kvm/kvm_main.c:4213 [inline]
kvm_vm_ioctl+0x7e3/0x42d0 virt/kvm/kvm_main.c:5178
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
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: 0033:0x7ff5d9d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff5dabbc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff5da026090 RCX: 00007ff5d9d9e159
RDX: 0000000000000000 RSI: 000000000000ae41 RDI: 0000000000000005
RBP: 00007ff5d9e3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff5da026128 R14: 00007ff5da026090 R15: 00007fff730b6718
</TASK>
----------------
Code disassembly (best guess):
0: e8 71 ed 6b 00 call 0x6bed76
5: b9 74 01 00 00 mov $0x174,%ecx
a: 0f 32 rdmsr
c: 48 c1 e2 20 shl $0x20,%rdx
10: 48 89 d3 mov %rdx,%rbx
13: 48 09 c3 or %rax,%rbx
16: e9 ba 01 00 00 jmp 0x1d5
1b: e8 56 ed 6b 00 call 0x6bed76
20: 89 db mov %ebx,%ebx
22: b8 00 4c 00 00 mov $0x4c00,%eax
27: 0f 79 c3 vmwrite %rbx,%rax
* 2a: 0f 86 f5 01 00 00 jbe 0x225 <-- trapping instruction
30: e8 41 ed 6b 00 call 0x6bed76
35: b9 76 01 00 00 mov $0x176,%ecx
3a: 0f 32 rdmsr
3c: 48 c1 e2 20 shl $0x20,%rdx
---
This report is generated by a bot. It may contain errors.
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next reply other threads:[~2026-09-20 14:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-20 14:21 syzbot [this message]
2026-09-20 20:16 ` [syzbot] [trace?] WARNING in check_buffer Steven Rostedt
2026-10-06 21:58 ` syzbot
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