syzbot

Unable to handle kernel paging request at virtual address dfff800000000000
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006
  CM = 0, WnR = 0
[dfff800000000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 9178 Comm: syz.7.1168 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : dequeue_head net/sched/sch_fq_codel.c:120 [inline]
pc : fq_codel_drop net/sched/sch_fq_codel.c:168 [inline]
pc : fq_codel_enqueue+0x844/0x1004 net/sched/sch_fq_codel.c:230
lr : fq_codel_drop net/sched/sch_fq_codel.c:162 [inline]
lr : fq_codel_enqueue+0x7c0/0x1004 net/sched/sch_fq_codel.c:230
sp : ffff8000209c7360
x29: ffff8000209c7490 x28: 0000000000000000 x27: 0000000000000000
x26: ffff8000209c7660 x25: 0000000000000001 x24: ffff700004138e84
x23: 0000000000000000 x22: 0000000000000003 x21: ffff0000fee60e00
x20: dfff800000000000 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000082dcf38 x15: 0000000000000002
x14: 0000000000000003 x13: 1ffff00002a70071 x12: 0000000000080000
x11: 0000000000004b2f x10: ffff800022ba9000 x9 : 1fffe0001fdcc1c0
x8 : 0000000000000000 x7 : ffff8000083c75d4 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000
x2 : ffff0000cc407b28 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 dequeue_head net/sched/sch_fq_codel.c:120 [inline]
 fq_codel_drop net/sched/sch_fq_codel.c:168 [inline]
 fq_codel_enqueue+0x844/0x1004 net/sched/sch_fq_codel.c:230
 cbs_child_enqueue net/sched/sch_cbs.c:95 [inline]
 cbs_enqueue_soft+0x150/0x234 net/sched/sch_cbs.c:128
 cbs_enqueue+0x58/0x6c net/sched/sch_cbs.c:136
 dev_qdisc_enqueue+0x5c/0x388 net/core/dev.c:3900
 __dev_xmit_skb net/core/dev.c:3989 [inline]
 __dev_queue_xmit+0xaf0/0x3154 net/core/dev.c:4337
 dev_queue_xmit+0x24/0x34 include/linux/netdevice.h:3051
 packet_snd net/packet/af_packet.c:3133 [inline]
 packet_sendmsg+0x3034/0x40ac net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x324/0x440 net/socket.c:2153
 __do_sys_sendto net/socket.c:2165 [inline]
 __se_sys_sendto net/socket.c:2161 [inline]
 __arm64_sys_sendto+0xe4/0x104 net/socket.c:2161
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: aa1503e0 961e1322 f94002b7 d343fee8 (38746908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	aa1503e0 	mov	x0, x21
   4:	961e1322 	bl	0xfffffffff8784c8c
   8:	f94002b7 	ldr	x23, [x21]
   c:	d343fee8 	lsr	x8, x23, #3
* 10:	38746908 	ldrb	w8, [x8, x20] <-- trapping instruction