8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 000000a0 pgd = 86c2cc00 [000000a0] *pgd=86c2f003, *pmd=e895d003 Internal error: Oops: 207 [#1] PREEMPT SMP ARM Modules linked in: CPU: 1 PID: 4125 Comm: iou-sqp-4115 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 : 86563ee0 ip : 868aa080 fp : 86563f2c r10: 00000000 r9 : 86562000 r8 : 00000000 r7 : 86ce1000 r6 : 86b75400 r5 : 86b75454 r4 : 86ce1000 r3 : 000000a0 r2 : 86562000 r1 : 000000a0 r0 : 86563ef4 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 30c5387d Table: 86c2cc00 DAC: 00000000 Process iou-sqp-4115 (pid: 4125, stack limit = 0x86562210) Stack: (0x86563ee0 to 0x86564000) 3ee0: 00000000 000000a0 00000000 868aa080 802a6878 86563ef4 86563ef4 56b92eae 3f00: 00000001 86ce1000 86b75454 86b75400 00000000 00000000 86562000 00000000 3f20: 86563fac 86563f30 80566f50 80561e60 86b75404 81f744cc 82a06d00 00000000 3f40: 80384db8 86b75400 868de880 86b75454 00000000 00000000 00000000 868aa080 3f60: 802a6878 86563f64 86563f64 2d756f69 2d707173 35313134 80258400 56b92eae 3f80: 00000000 86b75400 80566b80 00000000 00000000 00000000 00000000 00000000 3fa0: 00000000 86563fb0 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 r9:86562000 r8:00000000 r7:00000000 r6:86b75400 r5:86b75454 r4:86ce1000 [<80566b80>] (io_sq_thread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:158) Exception stack(0x86563fb0 to 0x86563ff8) 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 r4:86b75400 Code: e28830a0 e50b3048 f593f000 e1a01003 (e1913f9f) ---[ end trace b5c63f7c07940556 ]--- ---------------- 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