syzbot

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Unable to handle kernel paging request at virtual address fee04f3a when write
[fee04f3a] *pgd=80000080007003, *pmd=00000000
Internal error: Oops: a06 [#1] SMP ARM
Modules linked in:
CPU: 1 UID: 0 PID: 4033 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 : [<81417944>]    lr : [<81417930>]    psr: 60000013
sp : dfbe9cb0  ip : dfbe9cb0  fp : dfbe9ccc
r10: 00000001  r9 : 00000084  r8 : dfbe9d9c
r7 : 00004f37  r6 : 0000009b  r5 : 84557480  r4 : 00004f3a
r3 : 0000009b  r2 : fee04f3a  r1 : 00000001  r0 : 84557480
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 85c10fc0  DAC: 00000000
Register r0 information:
 slab kmalloc-192 start 84557480 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 84557480 pointer offset 0 size 192
Register r6 information: non-paged memory
Register r7 information: non-paged memory
Register r8 information: 2-page vmalloc region starting at 0xdfbe8000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2651
Register r9 information: non-paged memory
Register r10 information: non-paged memory
Register r11 information: 2-page vmalloc region starting at 0xdfbe8000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2651
Register r12 information: 2-page vmalloc region starting at 0xdfbe8000 allocated at kernel_clone+0xac/0x3ec kernel/fork.c:2651
Process syz.2.17 (pid: 4033, stack limit = 0xdfbe8000)
Stack: (0xdfbe9cb0 to 0xdfbea000)
9ca0:                                     814178e4 84557480 00004f37 00004f37
9cc0: dfbe9cec dfbe9cd0 8141761c 814178f0 00004f37 80515900 85b2c000 85b2c000
9ce0: dfbe9d0c dfbe9cf0 814179dc 814175d0 84557480 00000000 85b2c000 00004f37
9d00: dfbe9d4c dfbe9d10 81417b88 8141795c 200000c0 84557480 b5403587 00000000
9d20: 84557480 829d46a0 84557480 845574c4 dfbe9d88 84557480 00000000 82b28ad8
9d40: dfbe9d84 dfbe9d50 814066bc 81417b20 845574b0 00000000 dfbe9d74 200000c0
9d60: 84557480 b5403587 845574b0 84e2d400 40946400 00000003 dfbe9e44 dfbe9d88
9d80: 81402014 814065c0 35353238 00000000 00000000 00000000 00000000 00004f37
9da0: 00000005 00000002 00000401 00000001 00000cc7 00000fff 5c95239d 00000005
9dc0: 000003ff 00000802 00001600 00000001 00000001 00000009 0000e1cb 20000006
9de0: 00000004 00000003 00000395 40000005 fffffffd 00000001 fffffff5 ffffeadd
9e00: 00000003 0000003a 00000008 00000004 08000000 dffffffa 00000000 dddcf836
9e20: 00000000 851a1900 84557480 200000c0 845574b0 84e2d400 dfbe9f14 dfbe9e48
9e40: 81403008 81401f20 00000000 00000000 00000000 00000000 00000000 dddcf836
9e60: 00000000 00000000 824a45ec 0000005f 8400d7f8 00000064 845fc00c 84e2d400
9e80: dfbe9ee4 dfbe9e90 807b8b78 807af09c 00000064 00000001 00000000 dfbe9eac
9ea0: 85bf7790 834df908 00006400 0000000b dfbe9ea0 00000000 00000000 dddcf836
9ec0: 851a1900 40946400 200000c0 200000c0 851a1900 00000003 dfbe9ef4 dfbe9ee8
9ee0: 807b8c98 dddcf836 dfbe9f14 40946400 00000000 851a1900 200000c0 851a1900
9f00: 00000003 84e2d400 dfbe9fa4 dfbe9f18 805860e8 81402a58 dfbe9f4c dfbe9f28
9f20: 8034bc54 8034efe4 81ab1b24 81ab19f4 dfbe9f54 dfbe9f40 8025bc80 7e9ba930
9f40: dfbe9fa4 dfbe9f50 8034c4f0 8034bb60 00000000 7e9ba930 ffffffff 80233614
9f60: 00000000 00000000 00000000 00000000 00000000 dddcf836 dfbe9fac 00000000
9f80: 00000000 00326310 00000036 8020029c 84e2d400 00000036 00000000 dfbe9fa8
9fa0: 80200060 80585fc4 00000000 00000000 00000003 40946400 200000c0 00000000
9fc0: 00000000 00000000 00326310 00000036 00000000 003262e4 0000047d 00000000
9fe0: 7e9ba790 7e9ba780 000192bc 00132360 60000010 00000003 00000000 00000000
Call trace: 
[<814178e4>] (subdev_8255_io) from [<8141761c>] (subdev_8255_do_config+0x58/0x60 drivers/comedi/drivers/comedi_8255.c:115)
 r7:00004f37 r6:00004f37 r5:84557480 r4:814178e4
[<814175c4>] (subdev_8255_do_config) from [<814179dc>] (__subdev_8255_init drivers/comedi/drivers/comedi_8255.c:172 [inline])
[<814175c4>] (subdev_8255_do_config) from [<814179dc>] (subdev_8255_io_init+0x8c/0x9c drivers/comedi/drivers/comedi_8255.c:192)
 r4:85b2c000
[<81417950>] (subdev_8255_io_init) from [<81417b88>] (dev_8255_attach drivers/comedi/drivers/8255.c:82 [inline])
[<81417950>] (subdev_8255_io_init) from [<81417b88>] (dev_8255_attach+0x74/0x120 drivers/comedi/drivers/8255.c:46)
 r7:00004f37 r6:85b2c000 r5:00000000 r4:84557480
[<81417b14>] (dev_8255_attach) from [<814066bc>] (comedi_device_attach+0x108/0x250 drivers/comedi/drivers.c:1069)
 r10:82b28ad8 r9:00000000 r8:84557480 r7:dfbe9d88 r6:845574c4 r5:84557480
 r4:829d46a0
[<814065b4>] (comedi_device_attach) from [<81402014>] (do_devconfig_ioctl+0x100/0x220 drivers/comedi/comedi_fops.c:928)
 r10:00000003 r9:40946400 r8:84e2d400 r7:845574b0 r6:b5403587 r5:84557480
 r4:200000c0
[<81401f14>] (do_devconfig_ioctl) from [<81403008>] (comedi_unlocked_ioctl+0x5bc/0x1c2c drivers/comedi/comedi_fops.c:2240)
 r8:84e2d400 r7:845574b0 r6:200000c0 r5:84557480 r4:851a1900
[<81402a4c>] (comedi_unlocked_ioctl) from [<805860e8>] (vfs_ioctl fs/ioctl.c:51 [inline])
[<81402a4c>] (comedi_unlocked_ioctl) from [<805860e8>] (do_vfs_ioctl fs/ioctl.c:551 [inline])
[<81402a4c>] (comedi_unlocked_ioctl) from [<805860e8>] (__do_sys_ioctl fs/ioctl.c:595 [inline])
[<81402a4c>] (comedi_unlocked_ioctl) from [<805860e8>] (sys_ioctl+0x130/0xba0 fs/ioctl.c:583)
 r10:84e2d400 r9:00000003 r8:851a1900 r7:200000c0 r6:851a1900 r5:00000000
 r4:40946400
[<80585fb8>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdfbe9fa8 to 0xdfbe9ff0)
9fa0:                   00000000 00000000 00000003 40946400 200000c0 00000000
9fc0: 00000000 00000000 00326310 00000036 00000000 003262e4 0000047d 00000000
9fe0: 7e9ba790 7e9ba780 000192bc 00132360
 r10:00000036 r9:84e2d400 r8:8020029c r7:00000036 r6:00326310 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