syzbot

8<--- cut here ---
Unable to handle kernel NULL pointer dereference at virtual address 00000000 when read
[00000000] *pgd=83798003, *pmd=fe6bd003
Internal error: Oops: 207 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1 PID: 3002 Comm: syz-executor504 Not tainted 6.9.0-rc3-syzkaller #0
Hardware name: ARM-Versatile Express
PC is at page_zonenum include/linux/mmzone.h:1100 [inline]
PC is at __kmap_local_page_prot+0xc/0x74 mm/highmem.c:573
LR is at kmap_local_page include/linux/highmem-internal.h:73 [inline]
LR is at copy_page_to_iter+0xf8/0x184 lib/iov_iter.c:360
pc : [<80479f08>]    lr : [<807e99cc>]    psr: 60000013
sp : df96dca0  ip : df96dcb0  fp : df96dcac
r10: 00000018  r9 : 8285a4e8  r8 : 00000000
r7 : 00000000  r6 : 00000000  r5 : 00000000  r4 : 8440a800
r3 : 00c00000  r2 : 0000071f  r1 : 00000000  r0 : 00000000
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 84781040  DAC: 00000000
Register r0 information: NULL pointer
Register r1 information: NULL pointer
Register r2 information: non-paged memory
Register r3 information: non-paged memory
Register r4 information: slab kmalloc-1k start 8440a800 pointer offset 0 size 1024
Register r5 information: NULL pointer
Register r6 information: NULL pointer
Register r7 information: NULL pointer
Register r8 information: NULL pointer
Register r9 information: non-slab/vmalloc memory
Register r10 information: non-paged memory
Register r11 information: 2-page vmalloc region starting at 0xdf96c000 allocated at kernel_clone+0xac/0x3cc kernel/fork.c:2796
Register r12 information: 2-page vmalloc region starting at 0xdf96c000 allocated at kernel_clone+0xac/0x3cc kernel/fork.c:2796
Process syz-executor504 (pid: 3002, stack limit = 0xdf96c000)
Stack: (0xdf96dca0 to 0xdf96e000)
dca0: df96dce4 df96dcb0 807e99cc 80479f08 df96dcd4 df96df48 8024c880 8440a800
dcc0: 8440a800 00000000 00000000 00000000 000000d4 00000018 df96dd34 df96dce8
dce0: 8143329c 807e98e0 00000000 582a563e 83fbb400 83fbb4d0 835fc900 83fbb4d8
dd00: df96df48 00000000 df96dd8c 835fc900 000000d4 83fbb400 841c5400 00000000
dd20: 00000000 00000000 df96dda4 df96dd38 81655f50 814331b8 00000000 00000000
dd40: 00000000 00000000 00000000 00000000 835fc988 83fbb4ec 835fcb34 df96df38
dd60: 00000000 582a563e df96dd94 821a9848 00000000 582a563e df96df38 81655e00
dd80: df96df38 83349680 00000000 00000000 00000000 df96ddf4 df96ddc4 df96dda8
dda0: 81654fcc 81655e0c 00000000 00000000 00000000 81654f94 df96dde4 df96ddc8
ddc0: 813a287c 81654fa0 df96df38 83349680 200001c0 00000000 df96dea4 df96dde8
dde0: 813a2a7c 813a2838 00000000 00000000 00000001 00000000 00000000 00000000
de00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
de20: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
de40: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
de60: 00000000 00000000 00000000 00000000 00000000 582a563e 00000000 00000000
de80: df96df38 200001c0 00000000 83349680 841c5400 00000129 df96df24 df96dea8
dea0: 813a59c0 813a29f8 00000000 00000000 00000000 00000000 00000000 20000280
dec0: 000000d4 00000000 00000000 00000000 00000000 00000000 00000000 00000000
dee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 582a563e
df00: df96df24 83349680 00000000 200001c0 00000000 80200288 df96dfa4 df96df28
df20: 813a613c 813a5944 00000000 00000000 00000000 fffffff7 df96ddf4 00000000
df40: 00000000 00000000 00000000 00000000 20000280 000000d4 00000001 00000000
df60: 00000000 00000001 00000000 00000000 00000000 00000000 00000000 00000000
df80: df96dfa4 582a563e ffffffff 00000000 0008e070 00000129 00000000 df96dfa8
dfa0: 80200060 813a60d4 ffffffff 00000000 00000003 200001c0 00000000 00000000
dfc0: ffffffff 00000000 0008e070 00000129 20000080 00000000 0008a270 00000000
dfe0: 7ee5cc70 7ee5cc60 00010a8c 0002eb90 00000010 00000003 00000000 00000000
Call trace: 
[<80479efc>] (__kmap_local_page_prot) from [<807e99cc>] (kmap_local_page include/linux/highmem-internal.h:73 [inline])
[<80479efc>] (__kmap_local_page_prot) from [<807e99cc>] (copy_page_to_iter+0xf8/0x184 lib/iov_iter.c:360)
[<807e98d4>] (copy_page_to_iter) from [<8143329c>] (sk_msg_recvmsg+0xf0/0x3cc net/core/skmsg.c:437)
 r10:00000018 r9:000000d4 r8:00000000 r7:00000000 r6:00000000 r5:8440a800
 r4:8440a800
[<814331ac>] (sk_msg_recvmsg) from [<81655f50>] (unix_bpf_recvmsg net/unix/unix_bpf.c:73 [inline])
[<814331ac>] (sk_msg_recvmsg) from [<81655f50>] (unix_bpf_recvmsg+0x150/0x444 net/unix/unix_bpf.c:50)
 r10:00000000 r9:00000000 r8:00000000 r7:841c5400 r6:83fbb400 r5:000000d4
 r4:835fc900
[<81655e00>] (unix_bpf_recvmsg) from [<81654fcc>] (unix_dgram_recvmsg+0x38/0x4c net/unix/af_unix.c:2529)
 r10:df96ddf4 r9:00000000 r8:00000000 r7:00000000 r6:83349680 r5:df96df38
 r4:81655e00
[<81654f94>] (unix_dgram_recvmsg) from [<813a287c>] (sock_recvmsg_nosec net/socket.c:1046 [inline])
[<81654f94>] (unix_dgram_recvmsg) from [<813a287c>] (sock_recvmsg+0x50/0x78 net/socket.c:1068)
 r4:81654f94
[<813a282c>] (sock_recvmsg) from [<813a2a7c>] (____sys_recvmsg+0x90/0x158 net/socket.c:2803)
 r7:00000000 r6:200001c0 r5:83349680 r4:df96df38
[<813a29ec>] (____sys_recvmsg) from [<813a59c0>] (___sys_recvmsg+0x88/0xbc net/socket.c:2845)
 r10:00000129 r9:841c5400 r8:83349680 r7:00000000 r6:200001c0 r5:df96df38
 r4:00000000
[<813a5938>] (___sys_recvmsg) from [<813a613c>] (__sys_recvmsg net/socket.c:2875 [inline])
[<813a5938>] (___sys_recvmsg) from [<813a613c>] (__do_sys_recvmsg net/socket.c:2885 [inline])
[<813a5938>] (___sys_recvmsg) from [<813a613c>] (sys_recvmsg+0x74/0xb8 net/socket.c:2882)
 r8:80200288 r7:00000000 r6:200001c0 r5:00000000 r4:83349680
[<813a60c8>] (sys_recvmsg) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:66)
Exception stack(0xdf96dfa8 to 0xdf96dff0)
dfa0:                   ffffffff 00000000 00000003 200001c0 00000000 00000000
dfc0: ffffffff 00000000 0008e070 00000129 20000080 00000000 0008a270 00000000
dfe0: 7ee5cc70 7ee5cc60 00010a8c 0002eb90
 r7:00000129 r6:0008e070 r5:00000000 r4:ffffffff
Code: eaffffe8 e1a0c00d e92dd800 e24cb004 (e5901000) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	eaffffe8 	b	0xffffffa8
   4:	e1a0c00d 	mov	ip, sp
   8:	e92dd800 	push	{fp, ip, lr, pc}
   c:	e24cb004 	sub	fp, ip, #4
* 10:	e5901000 	ldr	r1, [r0] <-- trapping instruction