syzbot

comedi comedi3: 8255: I/O port conflict (0x80004f27,4)
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Unable to handle kernel paging request at virtual address fee00008 when write
[fee00008] *pgd=80000080007003, *pmd=00000000
Internal error: Oops: a06 [#1] SMP ARM
Modules linked in:
CPU: 0 UID: 0 PID: 4114 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 subdev_8255_io drivers/comedi/drivers/comedi_8255.c:47 [inline]
PC is at subdev_8255_io+0x60/0x6c drivers/comedi/drivers/comedi_8255.c:43
LR is at subdev_8255_io drivers/comedi/drivers/comedi_8255.c:47 [inline]
LR is at subdev_8255_io+0x4c/0x6c drivers/comedi/drivers/comedi_8255.c:43
pc : [<813d8668>]    lr : [<813d8654>]    psr: 60000013
sp : e0575cb8  ip : e0575cb8  fp : e0575cd4
r10: 00000001  r9 : 00000000  r8 : 00000084
r7 : 00000005  r6 : 0000009b  r5 : 84212300  r4 : 00000008
r3 : 0000009b  r2 : fee00008  r1 : 00000001  r0 : 84212300
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 30c5387d  Table: 85aa4980  DAC: fffffffd
Register r0 information: slab kmalloc-192 start 84212300 pointer offset 0 size 192
Register r1 information: non-paged memory
Register r2 information: 0-page vmalloc region starting at 0xfee00000 allocated at pci_reserve_io+0x0/0x38 arch/arm/mm/mmu.c:1055
Register r3 information: non-paged memory
Register r4 information: non-paged memory
Register r5 information: slab kmalloc-192 start 84212300 pointer offset 0 size 192
Register r6 information: non-paged memory
Register r7 information: non-paged memory
Register r8 information: non-paged memory
Register r9 information: NULL pointer
Register r10 information: non-paged memory
Register r11 information: 2-page vmalloc region starting at 0xe0574000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2609
Register r12 information: 2-page vmalloc region starting at 0xe0574000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2609
Process syz.2.17 (pid: 4114, stack limit = 0xe0574000)
Stack: (0xe0575cb8 to 0xe0576000)
5ca0:                                                       813d8608 84212300
5cc0: 00000005 00000005 e0575cf4 e0575cd8 813d8340 813d8614 00000005 80509a08
5ce0: 85a88084 85a88084 e0575d14 e0575cf8 813d8700 813d82f4 85a88084 84212300
5d00: e0575da8 00000005 e0575d54 e0575d18 813d88f4 813d8680 82af0fe0 84933f00
5d20: 828215b0 00000000 00000000 829d22d4 84212300 84212344 e0575d90 84212300
5d40: 00000000 82b24908 e0575d8c e0575d58 813c77ec 813d8844 200000c0 00000000
5d60: e0575d7c 200000c0 84212300 b5403587 200000c0 84198000 40946400 00000003
5d80: e0575e4c e0575d90 813c3338 813c76f0 35353238 00000000 00000000 00000000
5da0: 00000000 80004f27 00000005 00000002 00000401 00000001 00000cc7 00000fff
5dc0: 5c95239c 00000001 000003ff 00000006 00001600 00000001 00000002 00000009
5de0: 0000e1cb 00000006 00000004 00000010 00000395 8000008b fffffffe 0000000b
5e00: fffffff5 ffffeadb 00000003 0000003c fffffffd 00000000 00000000 dffffffa
5e20: 00000000 37898076 00000000 8558ca80 84212300 200000c0 200000c0 84198000
5e40: e0575f14 e0575e50 813c4304 813c3244 00000000 00000000 00000000 37898076
5e60: 00000000 00000000 8245d5b4 0000005f 83f43018 84212330 8416af3c 84198000
5e80: e0575ee4 e0575e90 807a5fa4 8079c39c 00000064 00000001 00000000 e0575eac
5ea0: 8592cb50 83428d48 00006400 0000000b e0575ea0 00000000 00000000 37898076
5ec0: 8558ca80 40946400 200000c0 200000c0 8558ca80 00000003 e0575ef4 e0575ee8
5ee0: 807a60c4 37898076 e0575f14 40946400 00000000 8558ca80 200000c0 8558ca80
5f00: 00000003 84198000 e0575fa4 e0575f18 80577dc8 813c3d34 e0575f4c e0575f28
5f20: 80347bbc 8034afa8 81a363f8 81a362c8 e0575f54 e0575f40 8025c478 7ed68920
5f40: e0575fa4 e0575f50 80348458 80347ac8 00000000 7ed68920 ffffffff 80234128
5f60: 00000000 00000000 00000000 00000000 00000000 37898076 e0575fac 00000000
5f80: 00000000 00316308 00000036 8020029c 84198000 00000036 00000000 e0575fa8
5fa0: 80200060 80577ca4 00000000 00000000 00000003 40946400 200000c0 00000000
5fc0: 00000000 00000000 00316308 00000036 00000000 003162dc 0000047b 00000000
5fe0: 7ed68780 7ed68770 000195a4 00132510 60000010 00000003 00000000 00000000
Call trace: 
[<813d8608>] (subdev_8255_io) from [<813d8340>] (subdev_8255_do_config+0x58/0x60 drivers/comedi/drivers/comedi_8255.c:115)
 r7:00000005 r6:00000005 r5:84212300 r4:813d8608
[<813d82e8>] (subdev_8255_do_config) from [<813d8700>] (__subdev_8255_init drivers/comedi/drivers/comedi_8255.c:172 [inline])
[<813d82e8>] (subdev_8255_do_config) from [<813d8700>] (subdev_8255_io_init+0x8c/0x9c drivers/comedi/drivers/comedi_8255.c:192)
 r4:85a88084
[<813d8674>] (subdev_8255_io_init) from [<813d88f4>] (dev_8255_attach drivers/comedi/drivers/8255.c:83 [inline])
[<813d8674>] (subdev_8255_io_init) from [<813d88f4>] (dev_8255_attach+0xbc/0x114 drivers/comedi/drivers/8255.c:46)
 r7:00000005 r6:e0575da8 r5:84212300 r4:85a88084
[<813d8838>] (dev_8255_attach) from [<813c77ec>] (comedi_device_attach+0x108/0x250 drivers/comedi/drivers.c:1007)
 r10:82b24908 r9:00000000 r8:84212300 r7:e0575d90 r6:84212344 r5:84212300
 r4:829d22d4
[<813c76e4>] (comedi_device_attach) from [<813c3338>] (do_devconfig_ioctl+0x100/0x220 drivers/comedi/comedi_fops.c:872)
 r10:00000003 r9:40946400 r8:84198000 r7:200000c0 r6:b5403587 r5:84212300
 r4:200000c0
[<813c3238>] (do_devconfig_ioctl) from [<813c4304>] (comedi_unlocked_ioctl+0x5dc/0x1c50 drivers/comedi/comedi_fops.c:2178)
 r8:84198000 r7:200000c0 r6:200000c0 r5:84212300 r4:8558ca80
[<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)
 r10:84198000 r9:00000003 r8:8558ca80 r7:200000c0 r6:8558ca80 r5:00000000
 r4:40946400
[<80577c98>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xe0575fa8 to 0xe0575ff0)
5fa0:                   00000000 00000000 00000003 40946400 200000c0 00000000
5fc0: 00000000 00000000 00316308 00000036 00000000 003162dc 0000047b 00000000
5fe0: 7ed68780 7ed68770 000195a4 00132510
 r10:00000036 r9:84198000 r8:8020029c r7:00000036 r6:00316308 r5:00000000
 r4:00000000
Code: e6ef3076 e0842002 e7f32052 e2422612 (e5c23000) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	e6ef3076 	uxtb	r3, r6
   4:	e0842002 	add	r2, r4, r2
   8:	e7f32052 	ubfx	r2, r2, #0, #20
   c:	e2422612 	sub	r2, r2, #18874368	@ 0x1200000
* 10:	e5c23000 	strb	r3, [r2] <-- trapping instruction