[syzbot] BUG: unable to handle kernel paging request in tomoyo_encode

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    65762d97e6fa Merge branch 'for-next/perf' 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=1152d68d880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=56d0c7c3a2304e8f
dashboard link: https://syzkaller.appspot.com/bug?extid=2f0d91a12931a37dd85e
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12f9e8a1880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13125fe5880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/52f702197b30/disk-65762d97.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/72189c2789ce/vmlinux-65762d97.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ec0349196c98/Image-65762d97.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2f0d91a12931a37dd85e at syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address 00480000001a0040
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
[00480000001a0040] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 3263 Comm: syz-executor425 Not tainted 6.1.0-rc6-syzkaller-32653-g65762d97e6fa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __kmem_cache_alloc_node+0x17c/0x350 mm/slub.c:3437
lr : slab_pre_alloc_hook mm/slab.h:712 [inline]
lr : slab_alloc_node mm/slub.c:3318 [inline]
lr : __kmem_cache_alloc_node+0x80/0x350 mm/slub.c:3437
sp : ffff80000ff3b990
x29: ffff80000ff3b9a0 x28: ffff0000c681b480 x27: 0000000000000006
x26: 000000000000001d x25: 00000000ffffffff x24: ffff800009443294
x23: 0000000000000011 x22: 00480000001a0000 x21: 0000000000000000
x20: 0000000000000d40 x19: ffff0000c0001200 x18: 0000000000000000
x17: 0000000000000000 x16: ffff80000dbe6158 x15: ffff0000c681b480
x14: 0000000000000010 x13: 0000000000000000 x12: ffff0000c681b480
x11: 0000000000000001 x10: 0000000000000000 x9 : 0000000000000040
x8 : 00000000000a8cb9 x7 : ffff8000084bf248 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 00000000000a8cc1
x2 : 0000000000000000 x1 : 0000000000000d40 x0 : fffffc00031ee180
Call trace:
 next_tid mm/slub.c:2349 [inline]
 slab_alloc_node mm/slub.c:3382 [inline]
 __kmem_cache_alloc_node+0x17c/0x350 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:954 [inline]
 __kmalloc+0xb4/0x140 mm/slab_common.c:968
 kmalloc include/linux/slab.h:558 [inline]
 kzalloc include/linux/slab.h:689 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x1d8/0x2d0 security/tomoyo/realpath.c:80
 tomoyo_mount_acl security/tomoyo/mount.c:150 [inline]
 tomoyo_mount_permission+0x2c8/0x5ac security/tomoyo/mount.c:237
 tomoyo_sb_mount+0x48/0x60 security/tomoyo/tomoyo.c:401
 security_sb_mount+0x5c/0xb8 security/security.c:979
 path_mount+0xa0/0x890 fs/namespace.c:3312
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __arm64_sys_mount+0x2c4/0x3c4 fs/namespace.c:3568
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
 el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584
Code: 54000ee1 34000eeb b9402a69 91002103 (f8696ada) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	54000ee1 	b.ne	0x1dc  // b.any
   4:	34000eeb 	cbz	w11, 0x1e0
   8:	b9402a69 	ldr	w9, [x19, #40]
   c:	91002103 	add	x3, x8, #0x8
* 10:	f8696ada 	ldr	x26, [x22, x9] <-- trapping instruction


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