syzbot

8<--- cut here ---
Unable to handle kernel paging request at virtual address fee02f00 when write
[fee02f00] *pgd=80000080007003, *pmd=00000000
Internal error: Oops: a06 [#1] SMP ARM
Modules linked in:
CPU: 1 UID: 0 PID: 4147 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 : [<813cb760>]    lr : [<813cb750>]    psr: 60000013
sp : e0401d30  ip : e0401d30  fp : e0401d54
r10: 82b24908  r9 : 00000003  r8 : 8415a3c0
r7 : e0401d90  r6 : 8415a3c0  r5 : 00000000  r4 : 00000000
r3 : fee02f00  r2 : 81e1765c  r1 : 00000001  r0 : 813cb3d0
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 855cdac0  DAC: 00000000
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 8415a3c0 pointer offset 0 size 192
Register r7 information: 2-page vmalloc region starting at 0xe0400000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2609
Register r8 information: slab kmalloc-192 start 8415a3c0 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 0xe0400000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2609
Register r12 information: 2-page vmalloc region starting at 0xe0400000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2609
Process syz.2.17 (pid: 4147, stack limit = 0xe0400000)
Stack: (0xe0401d30 to 0xe0402000)
1d20:                                     823ecc98 8415a3c0 829d1b3c 829d1b3c
1d40: 81e17b1c 8415a404 e0401d8c e0401d58 813c77ec 813cb5f8 20000300 00000000
1d60: e0401d7c 20000300 8415a3c0 b5403587 20000300 840abc00 40946400 00000001
1d80: e0401e4c e0401d90 813c3338 813c76f0 656d6f63 705f6964 6f707261 00007472
1da0: 00000000 00002f00 00000005 0000d09a ffffffff 00000003 fffffffe 20000004
1dc0: 00000003 00000ffe 7fffffff 0000000c 00000002 00000004 00000008 0000ffff
1de0: 00000006 00000005 000007ff 00000830 00000008 00010000 00000009 00000800
1e00: 00000101 00000002 00008001 00000007 00000003 00000004 00000005 0000070f
1e20: 00000000 9bd1fd6d 00000000 857503c0 8415a3c0 20000300 20000300 840abc00
1e40: e0401f14 e0401e50 813c4304 813c3244 00000000 00000000 00000000 9bd1fd6d
1e60: 00000000 00000000 8245d5b4 0000005f 83f26250 8415a3f0 83c56eac 840abc00
1e80: e0401ee4 e0401e90 807a5fa4 8079c39c 00000064 00000001 00000000 e0401eac
1ea0: 85a3e6d0 834e1d48 00006400 0000000b e0401ea0 00000000 00000000 9bd1fd6d
1ec0: 857503c0 40946400 20000300 20000300 857503c0 00000003 e0401ef4 e0401ee8
1ee0: 807a60c4 9bd1fd6d e0401f14 40946400 00000000 857503c0 20000300 857503c0
1f00: 00000003 840abc00 e0401fa4 e0401f18 80577dc8 813c3d34 e0401f4c e0401f28
1f20: 80347bbc 8034afa8 00000004 00010000 00000001 9bd1fd6d ffffff9c 7e9f7920
1f40: e0401fa4 e0401f50 80348458 80347ac8 00000000 7e9f7920 ffffffff 80234128
1f60: 00000000 00000000 00000000 00000000 00000000 9bd1fd6d 00000000 00000000
1f80: 00000000 00316308 00000036 8020029c 840abc00 00000036 00000000 e0401fa8
1fa0: 80200060 80577ca4 00000000 00000000 00000003 40946400 20000300 00000000
1fc0: 00000000 00000000 00316308 00000036 00000000 003162dc 0000047b 00000000
1fe0: 7e9f7780 7e9f7770 000195a4 00132510 60000010 00000003 00000000 00000000
Call trace: 
[<813cb5ec>] (parport_attach) from [<813c77ec>] (comedi_device_attach+0x108/0x250 drivers/comedi/drivers.c:1007)
 r6:8415a404 r5:81e17b1c r4:829d1b3c
[<813c76e4>] (comedi_device_attach) from [<813c3338>] (do_devconfig_ioctl+0x100/0x220 drivers/comedi/comedi_fops.c:872)
 r10:00000001 r9:40946400 r8:840abc00 r7:20000300 r6:b5403587 r5:8415a3c0
 r4:20000300
[<813c3238>] (do_devconfig_ioctl) from [<813c4304>] (comedi_unlocked_ioctl+0x5dc/0x1c50 drivers/comedi/comedi_fops.c:2178)
 r8:840abc00 r7:20000300 r6:20000300 r5:8415a3c0 r4:857503c0
[<813c3d28>] (comedi_unlocked_ioctl) from [<80577dc8>] (vfs_ioctl fs/ioctl.c:51 [inline])
[<813c3d28>] (comedi_unlocked_ioctl) from [<80577dc8>] (do_vfs_ioctl fs/ioctl.c:551 [inline])
[<813c3d28>] (comedi_unlocked_ioctl) from [<80577dc8>] (__do_sys_ioctl fs/ioctl.c:595 [inline])
[<813c3d28>] (comedi_unlocked_ioctl) from [<80577dc8>] (sys_ioctl+0x130/0xba0 fs/ioctl.c:583)
 r10:840abc00 r9:00000003 r8:857503c0 r7:20000300 r6:857503c0 r5:00000000
 r4:40946400
[<80577c98>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xe0401fa8 to 0xe0401ff0)
1fa0:                   00000000 00000000 00000003 40946400 20000300 00000000
1fc0: 00000000 00000000 00316308 00000036 00000000 003162dc 0000047b 00000000
1fe0: 7e9f7780 7e9f7770 000195a4 00132510
 r10:00000036 r9:840abc00 r8:8020029c r7:00000036 r6:00316308 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