syzbot

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Reader on commit with 12925 missed events
WARNING: kernel/trace/ring_buffer.c:7409 at ring_buffer_map_get_reader+0x63c/0x880 kernel/trace/ring_buffer.c:7409, CPU#1: syz.2.6905/24526
Modules linked in:
CPU: 1 UID: 0 PID: 24526 Comm: syz.2.6905 Tainted: G     U       L      syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ring_buffer_map_get_reader+0x63f/0x880 kernel/trace/ring_buffer.c:7409
Code: 48 c1 ea 03 80 3c 02 00 0f 85 4f 02 00 00 4c 3b a3 a0 00 00 00 0f 85 7b 19 17 ff e8 5b d7 fb ff 48 8d 3d 04 11 d1 0e 4c 89 fe <67> 48 0f b9 3a e9 e0 fc ff ff 4c 8b 7c 24 58 4c 8b 74 24 60 e8 38
RSP: 0018:ffffc9000e6cfd90 EFLAGS: 00010083
RAX: 00000000000007ba RBX: ffff88813fe9d000 RCX: ffffc90003b79000
RDX: 0000000000080000 RSI: 000000000000327d RDI: ffffffff90dd3190
RBP: ffff888034fed980 R08: 0000000000000007 R09: 0000000000000000
R10: 000000000000327d R11: ffff88813fe9d0b0 R12: ffff888034fed980
R13: dffffc0000000000 R14: ffff88813fe9d0a8 R15: 000000000000327d
FS:  00007fa48a2906c0(0000) GS:ffff88812445a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34d09ff8 CR3: 000000003262c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 tracing_buffers_ioctl+0x30d/0x400 kernel/trace/trace.c:8159
 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:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa48939bf79
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:00007fa48a290028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa489615fa0 RCX: 00007fa48939bf79
RDX: 0000000000000000 RSI: 0000000000005220 RDI: 0000000000000002
RBP: 00007fa4894327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa489616038 R14: 00007fa489615fa0 R15: 00007ffd59c64378
 </TASK>
----------------
Code disassembly (best guess):
   0:	48 c1 ea 03          	shr    $0x3,%rdx
   4:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   8:	0f 85 4f 02 00 00    	jne    0x25d
   e:	4c 3b a3 a0 00 00 00 	cmp    0xa0(%rbx),%r12
  15:	0f 85 7b 19 17 ff    	jne    0xff171996
  1b:	e8 5b d7 fb ff       	call   0xfffbd77b
  20:	48 8d 3d 04 11 d1 0e 	lea    0xed11104(%rip),%rdi        # 0xed1112b
  27:	4c 89 fe             	mov    %r15,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 e0 fc ff ff       	jmp    0xfffffd14
  34:	4c 8b 7c 24 58       	mov    0x58(%rsp),%r15
  39:	4c 8b 74 24 60       	mov    0x60(%rsp),%r14
  3e:	e8                   	.byte 0xe8
  3f:	38                   	.byte 0x38