8<--- cut here ---
Unable to handle kernel NULL pointer dereference at virtual address 000000a0
pgd = 86bfaf80
[000000a0] *pgd=86c04003, *pmd=e7000003
Internal error: Oops: 207 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 5224 Comm: iou-sqp-5215 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: ARM-Versatile Express
PC is at atomic_add arch/arm/include/asm/atomic.h:223 [inline]
PC is at atomic_inc include/linux/atomic-fallback.h:372 [inline]
PC is at io_uring_cancel_sqpoll+0xac/0x1a0 fs/io_uring.c:8926
LR is at io_sq_thread+0x3d0/0x6f8 fs/io_uring.c:6772
pc : [<80561f00>]    lr : [<80566f50>]    psr: 60000013
sp : 865e3ee0  ip : 86c0d140  fp : 865e3f2c
r10: 00000000  r9 : 865e2000  r8 : 00000000
r7 : 86d2a800  r6 : 86cd4700  r5 : 86cd4754  r4 : 86d2a800
r3 : 000000a0  r2 : 865e2000  r1 : 000000a0  r0 : 865e3ef4
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 30c5387d  Table: 86bfaf80  DAC: fffffffd
Process iou-sqp-5215 (pid: 5224, stack limit = 0x865e2210)
Stack: (0x865e3ee0 to 0x865e4000)
3ee0: 00000000 000000a0 00000000 86c0d140 802a6878 865e3ef4 865e3ef4 56b92eae
3f00: 00000001 86d2a800 86cd4754 86cd4700 00000000 00000000 865e2000 00000000
3f20: 865e3fac 865e3f30 80566f50 80561e60 86cd4704 81f744cc 82a06d00 00000000
3f40: 80384db8 86cd4700 835aa680 86cd4754 00000000 00000000 00000000 86c0d140
3f60: 802a6878 865e3f64 865e3f64 2d756f69 2d707173 35313235 80258400 56b92eae
3f80: 00000000 86cd4700 80566b80 00000000 00000000 00000000 00000000 00000000
3fa0: 00000000 865e3fb0 80200114 80566b8c 00000000 00000000 00000000 00000000
3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
3fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
Backtrace: 
[<80561e54>] (io_uring_cancel_sqpoll) from [<80566f50>] (io_sq_thread+0x3d0/0x6f8 fs/io_uring.c:6772)
 r10:00000000 r9:865e2000 r8:00000000 r7:00000000 r6:86cd4700 r5:86cd4754
 r4:86d2a800
[<80566b80>] (io_sq_thread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:158)
Exception stack(0x865e3fb0 to 0x865e3ff8)
3fa0:                                     00000000 00000000 00000000 00000000
3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
3fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:80566b80
 r4:86cd4700
Code: e28830a0 e50b3048 f593f000 e1a01003 (e1913f9f) 
---[ end trace b9b5604bbb983838 ]---
----------------
Code disassembly (best guess):
   0:	e28830a0 	add	r3, r8, #160	; 0xa0
   4:	e50b3048 	str	r3, [fp, #-72]	; 0xffffffb8
   8:	f593f000 	pldw	[r3]
   c:	e1a01003 	mov	r1, r3
* 10:	e1913f9f 	ldrex	r3, [r1] <-- trapping instruction