syzbot

8<--- cut here ---
Unable to handle kernel paging request at virtual address fee04f23 when write
[fee04f23] *pgd=80000080007003, *pmd=00000000
Internal error: Oops: a06 [#1] SMP ARM
Modules linked in:
CPU: 0 UID: 0 PID: 4026 Comm: syz.2.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
PC is at __raw_writeb arch/arm/include/asm/io.h:88 [inline]
PC is at parport_attach drivers/comedi/drivers/comedi_parport.c:289 [inline]
PC is at parport_attach+0x174/0x1d0 drivers/comedi/drivers/comedi_parport.c:224
LR is at parport_attach drivers/comedi/drivers/comedi_parport.c:289 [inline]
LR is at parport_attach+0x164/0x1d0 drivers/comedi/drivers/comedi_parport.c:224
pc : [<81401184>]    lr : [<81401174>]    psr: 60000013
sp : ea461d30  ip : ea461d30  fp : ea461d54
r10: 82b28b30  r9 : 00000003  r8 : 84577240
r7 : ea461d90  r6 : 84577240  r5 : 00000000  r4 : 00000000
r3 : fee04f23  r2 : 81e24f44  r1 : 00000001  r0 : 81400df4
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 30c5387d  Table: 859ac340  DAC: fffffffd
Register r0 information: non-slab/vmalloc memory
Register r1 information: non-paged memory
Register r2 information: non-slab/vmalloc memory
Register r3 information: 0-page vmalloc region starting at 0xfee00000 allocated at pci_reserve_io+0x0/0x38 arch/arm/mm/mmu.c:1055
Register r4 information: NULL pointer
Register r5 information: NULL pointer
Register r6 information: slab kmalloc-192 start 84577240 pointer offset 0 size 192
Register r7 information: 2-page vmalloc region starting at 0xea460000 allocated at kernel_clone+0xac/0x3f4 kernel/fork.c:2651
Register r8 information: slab kmalloc-192 start 84577240 pointer offset 0 size 192
Register r9 information: non-paged memory
Register r10 information: non-slab/vmalloc memory
Register r11 information: 2-page vmalloc region starting at 0xea460000 allocated at kernel_clone+0xac/0x3f4 kernel/fork.c:2651
Register r12 information: 2-page vmalloc region starting at 0xea460000 allocated at kernel_clone+0xac/0x3f4 kernel/fork.c:2651
Process syz.2.17 (pid: 4026, stack limit = 0xea460000)
Stack: (0xea461d30 to 0xea462000)
1d20:                                     8243d0ec 84577240 829d3948 829d3948
1d40: 81e25404 00000000 ea461d8c ea461d58 813fcdb0 8140101c 40946400 00000000
1d60: ea461d7c 200000c0 84577240 b5403587 40946400 85b03c00 00000003 84577270
1d80: ea461e4c ea461d90 813f86e0 813fccb0 656d6f63 705f6964 6f707261 00007472
1da0: 00000000 00004f23 00000005 00000002 04000401 00000001 40000cc7 00000fff
1dc0: 5c952399 00000005 000003ff 00000802 00000008 00010001 00000001 00000009
1de0: 0000e1cb 00000006 00000401 00000003 00000395 80000089 fffffffd 00000032
1e00: fffffff5 ffffeadb 00000007 0000003c 00000008 00000003 08000000 00002ec0
1e20: 00000000 b760f551 00000000 84dafe40 84577240 200000c0 40946400 85b03c00
1e40: ea461f14 ea461e50 813f9260 813f8618 00000000 b760f551 00000000 00000000
1e60: 824b15ec ea461ea4 0000005f 83fdbbe8 00000064 844e051c ea461ee4 ea461e88
1e80: 807b404c 807aa6c8 00000064 00000001 00000000 ea461ea4 85a10550 83424088
1ea0: 00006400 0000000b ea461e98 00000000 00000000 b760f551 ea461f24 84dafe40
1ec0: 40946400 200000c0 200000c0 84dafe40 00000003 85b03c00 ea461ef4 ea461ee8
1ee0: 807b417c b760f551 ea461f14 00000000 84dafe40 40946400 200000c0 84dafe40
1f00: 00000003 85b03c00 ea461fa4 ea461f18 8058223c 813f9168 ea461f4c ea461f28
1f20: 8034b6ac 8034ea2c 80233e34 804d7224 ea461f54 ea461f40 8025ba7c 00000004
1f40: ea461fa4 ea461f50 8034bfcc 8034b5e8 00000000 00000004 ffffffff 80233c18
1f60: 00000000 00000000 00000000 00000000 00000000 b760f551 ea461fac 00000000
1f80: 00000000 00346310 00000036 8020029c 85b03c00 00000036 00000000 ea461fa8
1fa0: 80200060 80582004 00000000 00000000 00000003 40946400 200000c0 00000000
1fc0: 00000000 00000000 00346310 00000036 003462d8 00000000 003462d8 003462e4
1fe0: 7ed0e790 7ed0e780 00018734 0012fc20 60000010 00000003 00000000 00000000
Call trace: 
[<81401010>] (parport_attach) from [<813fcdb0>] (comedi_device_attach+0x10c/0x248 drivers/comedi/drivers.c:1069)
 r6:00000000 r5:81e25404 r4:829d3948
[<813fcca4>] (comedi_device_attach) from [<813f86e0>] (do_devconfig_ioctl+0xd4/0x21c drivers/comedi/comedi_fops.c:928)
 r10:84577270 r9:00000003 r8:85b03c00 r7:40946400 r6:b5403587 r5:84577240
 r4:200000c0
[<813f860c>] (do_devconfig_ioctl) from [<813f9260>] (comedi_unlocked_ioctl+0x104/0x1c88 drivers/comedi/comedi_fops.c:2240)
 r8:85b03c00 r7:40946400 r6:200000c0 r5:84577240 r4:84dafe40
[<813f915c>] (comedi_unlocked_ioctl) from [<8058223c>] (vfs_ioctl fs/ioctl.c:51 [inline])
[<813f915c>] (comedi_unlocked_ioctl) from [<8058223c>] (do_vfs_ioctl fs/ioctl.c:551 [inline])
[<813f915c>] (comedi_unlocked_ioctl) from [<8058223c>] (__do_sys_ioctl fs/ioctl.c:595 [inline])
[<813f915c>] (comedi_unlocked_ioctl) from [<8058223c>] (sys_ioctl+0x244/0xb58 fs/ioctl.c:583)
 r10:85b03c00 r9:00000003 r8:84dafe40 r7:200000c0 r6:40946400 r5:84dafe40
 r4:00000000
[<80581ff8>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xea461fa8 to 0xea461ff0)
1fa0:                   00000000 00000000 00000003 40946400 200000c0 00000000
1fc0: 00000000 00000000 00346310 00000036 003462d8 00000000 003462d8 003462e4
1fe0: 7ed0e790 7ed0e780 00018734 0012fc20
 r10:00000036 r9:85b03c00 r8:8020029c r7:00000036 r6:00346310 r5:00000000
 r4:00000000
Code: e596306c e3a04000 e7f33053 e2433612 (e5c34000) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	e596306c 	ldr	r3, [r6, #108]	@ 0x6c
   4:	e3a04000 	mov	r4, #0
   8:	e7f33053 	ubfx	r3, r3, #0, #20
   c:	e2433612 	sub	r3, r3, #18874368	@ 0x1200000
* 10:	e5c34000 	strb	r4, [r3] <-- trapping instruction