From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>
Cc: Kostya Serebryany <kcc@google.com>,
Andrey Konovalov <adech.fo@gmail.com>,
Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Joonsoo Kim <js1304@gmail.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>,
kasan-dev <kasan-dev@googlegroups.com>,
LKML <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH] kasan: avoid overflowing quarantine size on low memory systems
Date: Tue, 2 Aug 2016 13:23:43 +0300 [thread overview]
Message-ID: <57A074AF.3040505@virtuozzo.com> (raw)
In-Reply-To: <CAG_fn=X2zahG9enAdSPxwqC-VV6nwK2PhuAXPyhOvASnXok9JQ@mail.gmail.com>
On 08/02/2016 01:07 PM, Alexander Potapenko wrote:
> On Tue, Aug 2, 2016 at 12:05 PM, Dmitry Vyukov <dvyukov@google.com> wrote:
>> On Tue, Aug 2, 2016 at 12:00 PM, Andrey Ryabinin
>>>
>>> Why WARN? I'd suggest pr_warn_once();
>>
>>
>> I would suggest to just do something useful. Setting quarantine
>> new_quarantine_size to 0 looks fine.
>> What would user do with this warning? Number of CPUs and amount of
>> memory are generally fixed. Why is it an issue for end user at all? We
>> still have some quarantine per-cpu. A WARNING means a [non-critical]
>> kernel bug. E.g. syzkaller will catch each and every boot of such
>> system as a bug.
> How about printk_once then?
> Silently setting the quarantine size to zero may puzzle the user.
>
Nope, user will not notice anything. So keeping it silent would be better.
Plus it's very unlikely that this will ever happen in real life.
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WARNING: multiple messages have this Message-ID (diff)
From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>
Cc: Kostya Serebryany <kcc@google.com>,
Andrey Konovalov <adech.fo@gmail.com>,
Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Joonsoo Kim <js1304@gmail.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>,
kasan-dev <kasan-dev@googlegroups.com>,
LKML <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH] kasan: avoid overflowing quarantine size on low memory systems
Date: Tue, 2 Aug 2016 13:23:43 +0300 [thread overview]
Message-ID: <57A074AF.3040505@virtuozzo.com> (raw)
In-Reply-To: <CAG_fn=X2zahG9enAdSPxwqC-VV6nwK2PhuAXPyhOvASnXok9JQ@mail.gmail.com>
On 08/02/2016 01:07 PM, Alexander Potapenko wrote:
> On Tue, Aug 2, 2016 at 12:05 PM, Dmitry Vyukov <dvyukov@google.com> wrote:
>> On Tue, Aug 2, 2016 at 12:00 PM, Andrey Ryabinin
>>>
>>> Why WARN? I'd suggest pr_warn_once();
>>
>>
>> I would suggest to just do something useful. Setting quarantine
>> new_quarantine_size to 0 looks fine.
>> What would user do with this warning? Number of CPUs and amount of
>> memory are generally fixed. Why is it an issue for end user at all? We
>> still have some quarantine per-cpu. A WARNING means a [non-critical]
>> kernel bug. E.g. syzkaller will catch each and every boot of such
>> system as a bug.
> How about printk_once then?
> Silently setting the quarantine size to zero may puzzle the user.
>
Nope, user will not notice anything. So keeping it silent would be better.
Plus it's very unlikely that this will ever happen in real life.
next prev parent reply other threads:[~2016-08-02 10:22 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-01 14:59 [PATCH] kasan: avoid overflowing quarantine size on low memory systems Alexander Potapenko
2016-08-01 14:59 ` Alexander Potapenko
2016-08-01 20:30 ` Andrew Morton
2016-08-01 20:30 ` Andrew Morton
2016-08-02 10:00 ` Andrey Ryabinin
2016-08-02 10:00 ` Andrey Ryabinin
2016-08-02 10:05 ` Dmitry Vyukov
2016-08-02 10:05 ` Dmitry Vyukov
2016-08-02 10:07 ` Alexander Potapenko
2016-08-02 10:07 ` Alexander Potapenko
2016-08-02 10:15 ` Dmitry Vyukov
2016-08-02 10:15 ` Dmitry Vyukov
2016-08-02 10:23 ` Andrey Ryabinin [this message]
2016-08-02 10:23 ` Andrey Ryabinin
2016-08-02 10:27 ` Alexander Potapenko
2016-08-02 10:27 ` Alexander Potapenko
2016-08-02 10:05 ` Alexander Potapenko
2016-08-02 10:05 ` Alexander Potapenko
2016-08-31 2:39 ` amanda4ray
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