3fc0: 00000000 00000000 00029734 00000036 7ef1c312 76fe46d0 7ef1c4a4 76fe420c
3fe0: 76fe4020 76fe4010 000163a0 0004bf80
 r10:00000036 r9:83a8a280 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=86e3d003, *pmd=fe701003
Internal error: Oops: 207 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1 PID: 8102 Comm: syz-executor.0 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 : 854d3ea0  ip : 854d3ec0  fp : 854d3ebc
r10: 855bd800  r9 : 855bdf00  r8 : 00000000
r7 : 855bdf00  r6 : 00000001  r5 : 855ec780  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: 8573ec00  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 855ec780 pointer offset 0 size 128
Register r6 information: non-paged memory
Register r7 information: slab kmalloc-64 start 855bdf00 pointer offset 0 size 64
Register r8 information: NULL pointer
Register r9 information: slab kmalloc-64 start 855bdf00 pointer offset 0 size 64
Register r10 information: slab kmalloc-64 start 855bd800 pointer offset 0 size 64
Register r11 information: non-slab/vmalloc memory
Register r12 information: non-slab/vmalloc memory
Process syz-executor.0 (pid: 8102, stack limit = 0x854d2000)
Stack: (0x854d3ea0 to 0x854d4000)
3ea0: 00000001 855ec780 00000001 855bdf00 854d3ef4 854d3ec0 803d9bc4 80444378
3ec0: 00000020 855bdf00 854d3eb8 00005760 00000001 855ec780 00000001 855e9540
3ee0: 00000004 848a5b00 854d3f14 854d3ef8 80497558 803d9a44 00005760 00000000
3f00: 855e9541 00000001 854d3fa4 854d3f18 804a4928 80497504 820a55ec 8209f3b0
3f20: 00029734 83a8a280 83a8a9a0 820a55f0 00000036 60000010 820a55e8 83a8a280
3f40: 820a55f0 00000036 854d3f64 854d3f58 816dae08 816dacd4 854d3f84 854d3f68
3f60: 816dab90 816dadf8 60000013 00000000 00029734 e7cfbc9f 854d3f9c 00000000
3f80: 00000000 00029734 00000036 802002a4 83a8a280 00000036 00000000 854d3fa8
3fa0: 80200060 804a4824 00000000 00000000 00000004 00005760 00000001 00000000
3fc0: 00000000 00000000 00029734 00000036 7ef1c312 76fe46d0 7ef1c4a4 76fe420c
3fe0: 76fe4020 76fe4010 000163a0 0004bf80 60000010 00000004 00000000 00000000
Backtrace: 
[<8044436c>] (__free_pages) from [<803d9bc4>] (watch_queue_set_size+0x18c/0x1b8 kernel/watch_queue.c:275)
 r7:855bdf00 r6:00000001 r5:855ec780 r4:00000001
[<803d9a38>] (watch_queue_set_size) from [<80497558>] (pipe_ioctl+0x60/0x100 fs/pipe.c:632)
 r10:848a5b00 r9:00000004 r8:855e9540 r7:00000001 r6:855ec780 r5:00000001
 r4:00005760
[<804974f8>] (pipe_ioctl) from [<804a4928>] (vfs_ioctl fs/ioctl.c:51 [inline])
[<804974f8>] (pipe_ioctl) from [<804a4928>] (do_vfs_ioctl fs/ioctl.c:834 [inline])
[<804974f8>] (pipe_ioctl) from [<804a4928>] (__do_sys_ioctl fs/ioctl.c:872 [inline])
[<804974f8>] (pipe_ioctl) from [<804a4928>] (sys_ioctl+0x110/0xaa0 fs/ioctl.c:860)
 r7:00000001 r6:855e9541 r5:00000000 r4:00005760
[<804a4818>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:64)
Exception stack(0x854d3fa8 to 0x854d3ff0)
3fa0:                   00000000 00000000 00000004 00005760 00000001 00000000
3fc0: 00000000 00000000 00029734 00000036 7ef1c312 76fe46d0 7ef1c4a4 76fe420c
3fe0: 76fe4020 76fe4010 000163a0 0004bf80
 r10:00000036 r9:83a8a280 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