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From:   Marco Elver <elver@google.com>
Date:   Mon, 28 Mar 2022 20:57:32 +0200
Message-ID: <CANpmjNMszqqOF6TA1RmE93=xRU9pA5oc4RBoAtS+sBWwvS5y4w@mail.gmail.com>
Subject: Re: [PATCH v2] mm: kfence: fix objcgs vector allocation
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Xiongchun duan <duanxiongchun@bytedance.com>
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On Mon, 28 Mar 2022 at 17:54, Muchun Song <songmuchun@bytedance.com> wrote:
[...]
> > >
> > > Btw, how did you test this?
> > >
>
> I have tested it with syzkaller with the following configs.
> And I didn't find any issues.
>
> CONFIG_KFENCE=y
> CONFIG_KFENCE_SAMPLE_INTERVAL=10
> CONFIG_KFENCE_NUM_OBJECTS=2550
> CONFIG_KFENCE_DEFERRABLE=n
> CONFIG_KFENCE_STATIC_KEYS=y
> CONFIG_KFENCE_STRESS_TEST_FAULTS=0

Hmm, I would have expected that you have some definitive test case
that shows the issue, and with the patch the issue is gone. Were there
issues triggered by syzkaller w/o this patch?

Thanks,
-- Marco