general protection fault in fb_videomode_to

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	BUG: unable to handle kernel paging request in fb_videomode_to_var fbdev				1	160d	156d	0/28	auto-obsoleted due to no activity on 2024/10/11 19:33
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 UID: 0 PID: 8368 Comm: syz.3.566 Not tainted 6.13.0-rc2-syzkaller-00036-g231825b2e1ff #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:fb_videomode_to_var+0x2e/0x5f0 drivers/video/fbdev/core/modedb.c:905
Code: 55 41 57 41 56 41 55 41 54 53 49 89 f6 49 89 fc 49 bd 00 00 00 00 00 fc ff df e8 bd cb 8c fc 4d 8d 7e 0c 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 ca 02 00 00 41 8b 1f 4c 89 e0 48 c1 e8
RSP: 0018:ffffc900034372c8 EFLAGS: 00010203
RAX: 0000000000000001 RBX: ffffffff9a6e4550 RCX: 0000000000080000
RDX: ffffc9000cfe9000 RSI: 00000000000006a9 RDI: 00000000000006aa
RBP: ffffc900034375b0 R08: ffffffff85129f93 R09: ffffffff85147ba5
R10: 0000000000000002 R11: ffff888026243c00 R12: ffffc90003437480
R13: dffffc0000000000 R14: 0000000000000000 R15: 000000000000000c
FS:  0000000000000000(0000) GS:ffff8880b8700000(0063) knlGS:00000000f5106b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000003040affc CR3: 000000005fcce000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 display_to_var drivers/video/fbdev/core/fbcon.c:924 [inline]
 fbcon_resize+0x631/0x1940 drivers/video/fbdev/core/fbcon.c:2059
 resize_screen drivers/tty/vt/vt.c:1112 [inline]
 vc_do_resize+0x7b2/0x17f0 drivers/tty/vt/vt.c:1192
 vc_resize include/linux/vt_kern.h:49 [inline]
 fbcon_modechanged+0x765/0x1200 drivers/video/fbdev/core/fbcon.c:2679
 do_fb_ioctl+0x71b/0x7b0 drivers/video/fbdev/core/fb_chrdev.c:92
 fb_compat_ioctl+0x2be/0xc80 drivers/video/fbdev/core/fb_chrdev.c:293
 __do_compat_sys_ioctl fs/ioctl.c:1004 [inline]
 __se_compat_sys_ioctl+0x502/0xc10 fs/ioctl.c:947
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf742d579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f510657c EFLAGS: 00000206 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 000000000000000a RCX: 0000000000004601
RDX: 0000000020000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:fb_videomode_to_var+0x2e/0x5f0 drivers/video/fbdev/core/modedb.c:905
Code: 55 41 57 41 56 41 55 41 54 53 49 89 f6 49 89 fc 49 bd 00 00 00 00 00 fc ff df e8 bd cb 8c fc 4d 8d 7e 0c 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 ca 02 00 00 41 8b 1f 4c 89 e0 48 c1 e8
RSP: 0018:ffffc900034372c8 EFLAGS: 00010203
RAX: 0000000000000001 RBX: ffffffff9a6e4550 RCX: 0000000000080000
RDX: ffffc9000cfe9000 RSI: 00000000000006a9 RDI: 00000000000006aa
RBP: ffffc900034375b0 R08: ffffffff85129f93 R09: ffffffff85147ba5
R10: 0000000000000002 R11: ffff888026243c00 R12: ffffc90003437480
R13: dffffc0000000000 R14: 0000000000000000 R15: 000000000000000c
FS:  0000000000000000(0000) GS:ffff8880b8700000(0063) knlGS:00000000f5106b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000003040affc CR3: 000000005fcce000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	55                   	push   %rbp
   1:	41 57                	push   %r15
   3:	41 56                	push   %r14
   5:	41 55                	push   %r13
   7:	41 54                	push   %r12
   9:	53                   	push   %rbx
   a:	49 89 f6             	mov    %rsi,%r14
   d:	49 89 fc             	mov    %rdi,%r12
  10:	49 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%r13
  17:	fc ff df
  1a:	e8 bd cb 8c fc       	call   0xfc8ccbdc
  1f:	4d 8d 7e 0c          	lea    0xc(%r14),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 ca 02 00 00    	jne    0x301
  37:	41 8b 1f             	mov    (%r15),%ebx
  3a:	4c 89 e0             	mov    %r12,%rax
  3d:	48                   	rex.W
  3e:	c1                   	.byte 0xc1
  3f:	e8                   	.byte 0xe8