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

[syzbot <syzbot+96e659d35b9d6b541152@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    aae703b02f92 Merge tag 'for-6.1-rc1-tag' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1686e478880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=883de36878e6d869
dashboard link: https://syzkaller.appspot.com/bug?extid=96e659d35b9d6b541152
compiler:       aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+96e659d35b9d6b541152@syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address ffff70000b978a00
KASAN: maybe wild-memory-access in range [0xffff80005cbc5000-0xffff80005cbc5007]
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
swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000045dfb000
[ffff70000b978a00] pgd=00000000bfbeb003, p4d=00000000bfbeb003, pud=00000000bfbea003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 2820 Comm: kworker/0:3 Tainted: G        W          6.1.0-rc1-syzkaller-00025-gaae703b02f92 #0
Hardware name: linux,dummy-virt (DT)
Workqueue: events free_ipc
pstate: 10000005 (nzcV daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : percpu_counter_add_batch+0x78/0x2f0 lib/percpu_counter.c:87
lr : percpu_counter_add_batch+0x44/0x2f0 lib/percpu_counter.c:87
sp : ffff8000120979c0
x29: ffff8000120979c0 x28: ffff0000151ff800 x27: 1fffe00002a3ff24
x26: ffff80005cbc5000 x25: ffff00000eeac7b0 x24: 1fffe00001dd58f6
x23: 000000007fffffff x22: ffff80000cc4e800 x21: 0000000000000000
x20: 0000000000000000 x19: ffff00000eeac758 x18: ffff00006a9cbbc0
x17: 0000000000000000 x16: 0000000000000000 x15: ffff800008d9c830
x14: ffff800008d78ecc x13: ffff800008d752d4 x12: ffff600002a3ff01
x11: 1fffe00002a3ff00 x10: ffff600002a3ff00 x9 : dfff800000000000
x8 : ffff0000151ff800 x7 : 00000000f1f1f1f1 x6 : dfff800000000000
x5 : ffff700002412f32 x4 : 1ffff000020ef1ac x3 : 1ffff0000b978a00
x2 : dfff800000000000 x1 : 0000000000000003 x0 : ffff80005cbc5000
Call trace:
 percpu_counter_add_batch+0x78/0x2f0 lib/percpu_counter.c:87
 percpu_counter_add_local include/linux/percpu_counter.h:75 [inline]
 percpu_counter_sub_local include/linux/percpu_counter.h:225 [inline]
 freeque+0x20c/0x364 ipc/msg.c:292
 free_ipcs+0xa0/0x160 ipc/namespace.c:125
 msg_exit_ns+0x38/0x60 ipc/msg.c:1334
 free_ipc_ns ipc/namespace.c:138 [inline]
 free_ipc+0xd0/0x1c0 ipc/namespace.c:157
 process_one_work+0x780/0x184c kernel/workqueue.c:2289
 worker_thread+0x3cc/0xc40 kernel/workqueue.c:2436
 kthread+0x23c/0x2a0 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860
Code: f2fbffe2 92400801 d343fc03 11000c21 (38e26862) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	f2fbffe2 	movk	x2, #0xdfff, lsl #48
   4:	92400801 	and	x1, x0, #0x7
   8:	d343fc03 	lsr	x3, x0, #3
   c:	11000c21 	add	w1, w1, #0x3
* 10:	38e26862 	ldrsb	w2, [x3, x2] <-- trapping instruction


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