ffc0: 00000000 00000000 00029734 00000036 7ec59312 76f546d0 7ec594a4 76f5420c
ffe0: 76f54020 76f54010 000163a0 0004bf80
 r10:00000036 r9:86390000 r8:802002a4 r7:00000036 r6:00029734 r5:00000000
 r4:00000000
8<--- cut here ---
Unable to handle kernel NULL pointer dereference at virtual address 0000001c
[0000001c] *pgd=84d2b003, *pmd=fe571003
Internal error: Oops: 207 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1 PID: 2838 Comm: syz-executor.1 Not tainted 5.17.0-rc8-syzkaller #0
Hardware name: ARM-Versatile Express
PC is at atomic_read include/linux/atomic/atomic-instrumented.h:28 [inline]
PC is at page_ref_count include/linux/page_ref.h:67 [inline]
PC is at put_page_testzero include/linux/mm.h:717 [inline]
PC is at __free_pages+0xc/0xd8 mm/page_alloc.c:5473
LR is at watch_queue_set_size+0x18c/0x1b8 kernel/watch_queue.c:275
pc : [<80444378>]    lr : [<803d9bc4>]    psr: 60000013
sp : 84f4fea0  ip : 84f4fec0  fp : 84f4febc
r10: 8601cd40  r9 : 8601cc40  r8 : 00000000
r7 : 8601cc40  r6 : 00000001  r5 : 85633300  r4 : 00000001
r3 : 00000000  r2 : 00000000  r1 : 00000000  r0 : 00000000
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 8601c3c0  DAC: 00000000
Register r0 information: NULL pointer
Register r1 information: NULL pointer
Register r2 information: NULL pointer
Register r3 information: NULL pointer
Register r4 information: non-paged memory
Register r5 information: slab kmalloc-cg-128 start 85633300 pointer offset 0 size 128
Register r6 information: non-paged memory
Register r7 information: slab kmalloc-64 start 8601cc40 pointer offset 0 size 64
Register r8 information: NULL pointer
Register r9 information: slab kmalloc-64 start 8601cc40 pointer offset 0 size 64
Register r10 information: slab kmalloc-64 start 8601cd40 pointer offset 0 size 64
Register r11 information: non-slab/vmalloc memory
Register r12 information: non-slab/vmalloc memory
Process syz-executor.1 (pid: 2838, stack limit = 0x84f4e000)
Stack: (0x84f4fea0 to 0x84f50000)
fea0: 00000001 85633300 00000001 8601cc40 84f4fef4 84f4fec0 803d9bc4 80444378
fec0: 00000020 8601cc40 84f4feb8 00005760 00000008 85633300 00000008 8512c180
fee0: 00000003 84973290 84f4ff14 84f4fef8 80497540 803d9a44 00005760 00000000
ff00: 8512c181 00000008 84f4ffa4 84f4ff18 804a4910 804974ec 820a55ec 8209f3b0
ff20: 00029734 86390000 86390720 820a55f0 00000036 60000010 820a55e8 86390000
ff40: 820a55f0 00000036 84f4ff64 84f4ff58 816dafd0 816dae9c 84f4ff84 84f4ff68
ff60: 816dad58 816dafc0 60000013 00000000 00029734 e7cfbc9f 84f4ff9c 00000000
ff80: 00000000 00029734 00000036 802002a4 86390000 00000036 00000000 84f4ffa8
ffa0: 80200060 804a480c 00000000 00000000 00000003 00005760 00000008 00000000
ffc0: 00000000 00000000 00029734 00000036 7ec59312 76f546d0 7ec594a4 76f5420c
ffe0: 76f54020 76f54010 000163a0 0004bf80 60000010 00000003 00000000 00000000
Backtrace: 
[<8044436c>] (__free_pages) from [<803d9bc4>] (watch_queue_set_size+0x18c/0x1b8 kernel/watch_queue.c:275)
 r7:8601cc40 r6:00000001 r5:85633300 r4:00000001
[<803d9a38>] (watch_queue_set_size) from [<80497540>] (pipe_ioctl+0x60/0x100 fs/pipe.c:632)
 r10:84973290 r9:00000003 r8:8512c180 r7:00000008 r6:85633300 r5:00000008
 r4:00005760
[<804974e0>] (pipe_ioctl) from [<804a4910>] (vfs_ioctl fs/ioctl.c:51 [inline])
[<804974e0>] (pipe_ioctl) from [<804a4910>] (do_vfs_ioctl fs/ioctl.c:834 [inline])
[<804974e0>] (pipe_ioctl) from [<804a4910>] (__do_sys_ioctl fs/ioctl.c:872 [inline])
[<804974e0>] (pipe_ioctl) from [<804a4910>] (sys_ioctl+0x110/0xaa0 fs/ioctl.c:860)
 r7:00000008 r6:8512c181 r5:00000000 r4:00005760
[<804a4800>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:64)
Exception stack(0x84f4ffa8 to 0x84f4fff0)
ffa0:                   00000000 00000000 00000003 00005760 00000008 00000000
ffc0: 00000000 00000000 00029734 00000036 7ec59312 76f546d0 7ec594a4 76f5420c
ffe0: 76f54020 76f54010 000163a0 0004bf80
 r10:00000036 r9:86390000 r8:802002a4 r7:00000036 r6:00029734 r5:00000000
 r4:00000000
Code: e7f001f2 e1a0c00d e92dd8f0 e24cb004 (e590301c) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	e7f001f2 	udf	#18
   4:	e1a0c00d 	mov	ip, sp
   8:	e92dd8f0 	push	{r4, r5, r6, r7, fp, ip, lr, pc}
   c:	e24cb004 	sub	fp, ip, #4
* 10:	e590301c 	ldr	r3, [r0, #28] <-- trapping instruction