BUG: unable to handle kernel paging request in drm_fb_helper_damage_work

[Hao Sun]

Hello,

When using Healer to fuzz the latest Linux kernel, the following crash
was triggered.

HEAD commit: 42d43c92fc57  Merge branch 'for-linus'
git tree: upstream
console output:
https://drive.google.com/file/d/1TXbZJ5Reefwpvr_wk3N1rGVKIMnF6fbP/view?usp=sharing
kernel config: https://drive.google.com/file/d/15vWoQRbJuuMu4ovWhUm1h4SrHyNwK8im/view?usp=sharing

Sorry, I don't have a reproducer for this crash, hope the symbolized
report can help.
If you fix this issue, please add the following tag to the commit:
Reported-by: Hao Sun <sunhao.th at gmail.com>

BUG: unable to handle page fault for address: ffffc900085e8070
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 10c00067 P4D 10c00067 PUD 10dbc067 PMD 1c94d067 PTE 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 3 PID: 33 Comm: kworker/3:0 Not tainted 5.15.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Workqueue: events drm_fb_helper_damage_work
RIP: 0010:rep_movs arch/x86/lib/iomem.c:12 [inline]
RIP: 0010:memcpy_toio+0x83/0xe0 arch/x86/lib/iomem.c:57
Code: 7a fd 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 44 73 7a fd 4d 85
ed 75 2e e8 ba 71 7a fd 48 89 e9 48 89 df 4c 89 e6 48 c1 e9 02 <f3> a5
40 f6 c5 02 74 02 66 a5 40 f6 c5 01 74 01 a4 5b 5d 41 5c 41
RSP: 0018:ffffc90000887be0 EFLAGS: 00010212
RAX: 0000000000000000 RBX: ffffc900085e8070 RCX: 000000000000094c
RDX: 0000000000000000 RSI: ffffc90006599070 RDI: ffffc900085e8070
RBP: 0000000000002530 R08: ffffffff83fbd9c6 R09: 0000000000000000
R10: 0000000000000007 R11: fffff52000110f56 R12: ffffc90006599070
R13: 0000000000000000 R14: ffff888019db0140 R15: ffffc90006599070
FS:  0000000000000000(0000) GS:ffff888135d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900085e8070 CR3: 000000001d3fd000 CR4: 0000000000350ee0
Call Trace:
 dma_buf_map_memcpy_to ./include/linux/dma-buf-map.h:245 [inline]
 drm_fb_helper_damage_blit_real drivers/gpu/drm/drm_fb_helper.c:388 [inline]
 drm_fb_helper_damage_blit drivers/gpu/drm/drm_fb_helper.c:419 [inline]
 drm_fb_helper_damage_work+0x76d/0xb00 drivers/gpu/drm/drm_fb_helper.c:450
 process_one_work+0x9df/0x16d0 kernel/workqueue.c:2297
 worker_thread+0x90/0xed0 kernel/workqueue.c:2444
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
CR2: ffffc900085e8070
---[ end trace 000e7483a76d6bd7 ]---
RIP: 0010:rep_movs arch/x86/lib/iomem.c:12 [inline]
RIP: 0010:memcpy_toio+0x83/0xe0 arch/x86/lib/iomem.c:57
Code: 7a fd 49 89 dd 31 ff 41 83 e5 02 4c 89 ee e8 44 73 7a fd 4d 85
ed 75 2e e8 ba 71 7a fd 48 89 e9 48 89 df 4c 89 e6 48 c1 e9 02 <f3> a5
40 f6 c5 02 74 02 66 a5 40 f6 c5 01 74 01 a4 5b 5d 41 5c 41
RSP: 0018:ffffc90000887be0 EFLAGS: 00010212
RAX: 0000000000000000 RBX: ffffc900085e8070 RCX: 000000000000094c
RDX: 0000000000000000 RSI: ffffc90006599070 RDI: ffffc900085e8070
RBP: 0000000000002530 R08: ffffffff83fbd9c6 R09: 0000000000000000
R10: 0000000000000007 R11: fffff52000110f56 R12: ffffc90006599070
R13: 0000000000000000 R14: ffff888019db0140 R15: ffffc90006599070
FS:  0000000000000000(0000) GS:ffff888135d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc900085e8070 CR3: 000000001d3fd000 CR4: 0000000000350ee0
----------------
Code disassembly (best guess):
   0: 7a fd                jp     0xffffffff
   2: 49 89 dd              mov    %rbx,%r13
   5: 31 ff                xor    %edi,%edi
   7: 41 83 e5 02          and    $0x2,%r13d
   b: 4c 89 ee              mov    %r13,%rsi
   e: e8 44 73 7a fd        callq  0xfd7a7357
  13: 4d 85 ed              test   %r13,%r13
  16: 75 2e                jne    0x46
  18: e8 ba 71 7a fd        callq  0xfd7a71d7
  1d: 48 89 e9              mov    %rbp,%rcx
  20: 48 89 df              mov    %rbx,%rdi
  23: 4c 89 e6              mov    %r12,%rsi
  26: 48 c1 e9 02          shr    $0x2,%rcx
* 2a: f3 a5                rep movsl %ds:(%rsi),%es:(%rdi) <--
trapping instruction
  2c: 40 f6 c5 02          test   $0x2,%bpl
  30: 74 02                je     0x34
  32: 66 a5                movsw  %ds:(%rsi),%es:(%rdi)
  34: 40 f6 c5 01          test   $0x1,%bpl
  38: 74 01                je     0x3b
  3a: a4                    movsb  %ds:(%rsi),%es:(%rdi)
  3b: 5b                    pop    %rbx
  3c: 5d                    pop    %rbp
  3d: 41 5c                pop    %r12
  3f: 41                    rex.B