[syzbot] [can?] general protection fault in can_rx_unregister (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4b4362973b6f Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=15e86d96580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a834c6344141a58b
dashboard link: https://syzkaller.appspot.com/bug?extid=8ed98cbd0161632bce95
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111f147e580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17942ac8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f69f86c90ee5/disk-4b436297.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/79fa7b33aaab/vmlinux-4b436297.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ef080156d0de/Image-4b436297.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8ed98c...@syzkaller.appspotmail.com

bond1: (slave vxcan3): Setting fail_over_mac to active for active-backup mode
bond1: (slave vxcan3): making interface the new active one
bond1: (slave vxcan3): Enslaving as an active interface with an up link
Unable to handle kernel paging request at virtual address dfff800000000005
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
Mem abort info:
ESR = 0x0000000096000005
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x05: level 1 translation fault
Data abort info:
ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000005] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1] SMP
Modules linked in:
CPU: 0 UID: 0 PID: 4947 Comm: syz.0.86 Not tainted syzkaller #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : can_rx_unregister+0x124/0x560 net/can/af_can.c:537
lr : can_rx_unregister+0x11c/0x560 net/can/af_can.c:531
sp : ffff800096267a40
x29: ffff800096267a60 x28: dfff800000000000 x27: ffff700012c4cf5c
x26: ffff0000d755ae48 x25: ffff0000c5c9ec00 x24: 0000000000000000
x23: ffff80008597d660 x22: ffff0000d9aa8000 x21: ffff0000cc740000
x20: 0000000000000028 x19: ffff0000cc740108 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
x14: 00000000ffff8000 x13: 0000000000000001 x12: 0000000000000004
x11: ffff700012c4cf30 x10: 0000000000ff0100 x9 : 0000000000000201
x8 : 0000000000000005 x7 : ffff80008594bef0 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008594ba58
x2 : 0000000000000001 x1 : ffff0000d5110000 x0 : 0000000000000028
Call trace:
can_rx_unregister+0x124/0x560 net/can/af_can.c:531 (P)
isotp_release+0x500/0x9d8 net/can/isotp.c:1232
__sock_release+0xa0/0x1d4 net/socket.c:722
sock_close+0x24/0x38 net/socket.c:1514
__fput+0x340/0x744 fs/file_table.c:510
____fput+0x20/0x30 fs/file_table.c:538
task_work_run+0x1c4/0x254 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0x10c/0x17c kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
arm64_syscall_exit_to_user_mode arch/arm64/kernel/entry-common.c:88 [inline]
el0_svc+0x18c/0x260 arch/arm64/kernel/entry-common.c:741
el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594
Code: aa1803e2 97ffff00 d343fc08 aa0003f4 (387c6908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: aa1803e2 mov x2, x24
4: 97ffff00 bl 0xfffffffffffffc04
8: d343fc08 lsr x8, x0, #3
c: aa0003f4 mov x20, x0
* 10: 387c6908 ldrb w8, [x8, x28] <-- trapping instruction


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