[syzbot] KASAN: slab-out-of-bounds Read in riscv_intc_irq

[Kefeng Wang]

On 2021/3/18 22:11, Dmitry Vyukov wrote:
> On Thu, Mar 18, 2021 at 1:21 PM Kefeng Wang <wangkefeng.wang at huawei.com> wrote:
>> On 2021/3/14 18:47, Dmitry Vyukov wrote:
>>> On Sun, Mar 14, 2021 at 11:14 AM syzbot
>>> <syzbot+005654dd9b8f26bd4c07 at syzkaller.appspotmail.com> wrote:
>>>> Hello,
>>>>
>>>> syzbot found the following issue on:
>>>>
>>>> HEAD commit:    0d7588ab riscv: process: Fix no prototype for arch_dup_tas..
>>>> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=15a35756d00000
>>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=81c0b708b31626cc
>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=005654dd9b8f26bd4c07
>>>> userspace arch: riscv64
>>>>
>>>> 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+005654dd9b8f26bd4c07 at syzkaller.appspotmail.com
>>>>
>>>> ==================================================================
>>>> BUG: KASAN: slab-out-of-bounds in riscv_intc_irq+0x24/0xcc drivers/irqchip/irq-riscv-intc.c:24
>>>> Read of size 8 at addr ffffffe00c963bd0 by task kworker/1:1/4388
>>>>
>>>> CPU: 1 PID: 4388 Comm: kworker/1:1 Not tainted 5.12.0-rc2-syzkaller-00467-g0d7588ab9ef9 #0
>>>> Hardware name: riscv-virtio,qemu (DT)
>>>> Workqueue: events nsim_dev_trap_report_work
>>>> Call Trace:
>>>> [<ffffffe0000096c0>] walk_stackframe+0x0/0x23c arch/riscv/kernel/traps.c:201
>>>>
>>>> Allocated by task 76347056:
>>>> (stack is not available)
>>>>
>>>> Last potentially related work creation:
>>> There seems to be some issue with riscv stack unwinder.
>>> This does not have stacks.
>> Hi, could you test with the following  patch about the no stack
>> issue(from v5.11-rc4), I made a mistake when do some cleanup...
>>
>> https://lore.kernel.org/linux-riscv/ce5b3533-b75d-c31c-4319-9d29769bbbd5@huawei.com/T/#t
> Hi Kefeng,
>
> Please see:
> http://bit.do/syzbot#no-custom-patches
>
> Is a unit-test for this possible? Fuzzing is not a replacement for unit testing.

ok, I mean that the issue about stack unwinder which may cause by my 
previous patch,

if some one want the stack back, it could try the bugfix.

> .
>