[v6.1] BUG: unable to handle kernel paging request in rxrpc_kernel_get_srtt

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10e5fe32580000
kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=158541db5013237b4fad
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d420eb944682/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/affae450ab23/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b9e6919ed519/Image-fb28aa72.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+158541...@syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address dfff800000000003
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
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
[dfff800000000003] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4379 Comm: kworker/0:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Workqueue: kafsd afs_process_async_call
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : rxrpc_kernel_get_srtt+0x34/0x124 net/rxrpc/peer_object.c:518
lr : rxrpc_kernel_get_srtt+0x2c/0x124 net/rxrpc/peer_object.c:517
sp : ffff800021377960
x29: ffff800021377970 x28: 1fffe0001f112c3f x27: ffff0000dc18710a
x26: 0000000000000000 x25: ffff0000c3608300 x24: dfff800000000000
x23: ffff70000426ef38 x22: ffff0000f88960f0 x21: dfff800000000000
x20: 0000000000000018 x19: ffff8000213779e0 x18: 1fffe00033e7277e
x17: ffff80001537d000 x16: ffff8000082f2844 x15: 0000000000000000
x14: 0000000000000001 x13: 1fffe0001b830e03 x12: 0000000000000000
x11: ff00800010fcf3ac x10: 0000000000000000 x9 : ffff800010fcf3ac
x8 : 0000000000000003 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff8000186b5f68 x4 : 0000000000000008 x3 : ffff800009c9663c
x2 : ffff8000213779e0 x1 : 0000000000000000 x0 : ffff0000e19cb600
Call trace:
rxrpc_kernel_get_srtt+0x34/0x124 net/rxrpc/peer_object.c:518
afs_vlserver_probe_result+0x4dc/0x9e8 fs/afs/vl_probe.c:118
afs_deliver_to_call+0x9a4/0xec0 fs/afs/rxrpc.c:563
afs_process_async_call+0x90/0xf8 fs/afs/rxrpc.c:703
process_one_work+0x7e4/0x13bc kernel/workqueue.c:2292
worker_thread+0x8cc/0xfe8 kernel/workqueue.c:2439
kthread+0x254/0x2e0 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
Code: f2fbfff5 97c099c9 91006294 d343fe88 (38756908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: f2fbfff5 movk x21, #0xdfff, lsl #48
4: 97c099c9 bl 0xffffffffff026728
8: 91006294 add x20, x20, #0x18
c: d343fe88 lsr x8, x20, #3
* 10: 38756908 ldrb w8, [x8, x21] <-- trapping instruction


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