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From: Alexander Potapenko <glider@google.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Dave Jones <davej@codemonkey.org.uk>,
	Vegard Nossum <vegard.nossum@oracle.com>,
	Sasha Levin <alexander.levin@verizon.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	kasan-dev <kasan-dev@googlegroups.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH 6/6] kasan: improve double-free reports.
Date: Tue, 2 Aug 2016 14:53:50 +0200	[thread overview]
Message-ID: <CAG_fn=ViiZ+WnL_c6vMg5-4HFeBjMJfm9RU15XO6uVKet+YD_w@mail.gmail.com> (raw)
In-Reply-To: <57A0933F.8000706@virtuozzo.com>

On Tue, Aug 2, 2016 at 2:34 PM, Andrey Ryabinin <aryabinin@virtuozzo.com> wrote:
>
>
> On 08/02/2016 02:39 PM, Alexander Potapenko wrote:
>
>>> +static void kasan_end_report(unsigned long *flags)
>>> +{
>>> +       pr_err("==================================================================\n");
>>> +       add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
>> Don't we want to add the taint as early as possible once we've
>> detected the error?
>
> What for?
> It certainly shouldn't be before dump_stack(), otherwise on the first report the kernel will claimed as tainted.
Ah, got it. Fair enough.
>
>>>
>>> +void kasan_report_double_free(struct kmem_cache *cache, void *object,
>>> +                       s8 shadow)
>>> +{
>>> +       unsigned long flags;
>>> +
>>> +       kasan_start_report(&flags);
>>> +       pr_err("BUG: Double free or corrupt pointer\n");
>> How about "Double free or freeing an invalid pointer\n"?
>> I think "corrupt pointer" doesn't exactly reflect where the bug is.
>
> Ok
>



-- 
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Straße, 33
80636 München

Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg

WARNING: multiple messages have this Message-ID (diff)
From: Alexander Potapenko <glider@google.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Dave Jones <davej@codemonkey.org.uk>,
	Vegard Nossum <vegard.nossum@oracle.com>,
	Sasha Levin <alexander.levin@verizon.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	kasan-dev <kasan-dev@googlegroups.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH 6/6] kasan: improve double-free reports.
Date: Tue, 2 Aug 2016 14:53:50 +0200	[thread overview]
Message-ID: <CAG_fn=ViiZ+WnL_c6vMg5-4HFeBjMJfm9RU15XO6uVKet+YD_w@mail.gmail.com> (raw)
In-Reply-To: <57A0933F.8000706@virtuozzo.com>

On Tue, Aug 2, 2016 at 2:34 PM, Andrey Ryabinin <aryabinin@virtuozzo.com> wrote:
>
>
> On 08/02/2016 02:39 PM, Alexander Potapenko wrote:
>
>>> +static void kasan_end_report(unsigned long *flags)
>>> +{
>>> +       pr_err("==================================================================\n");
>>> +       add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
>> Don't we want to add the taint as early as possible once we've
>> detected the error?
>
> What for?
> It certainly shouldn't be before dump_stack(), otherwise on the first report the kernel will claimed as tainted.
Ah, got it. Fair enough.
>
>>>
>>> +void kasan_report_double_free(struct kmem_cache *cache, void *object,
>>> +                       s8 shadow)
>>> +{
>>> +       unsigned long flags;
>>> +
>>> +       kasan_start_report(&flags);
>>> +       pr_err("BUG: Double free or corrupt pointer\n");
>> How about "Double free or freeing an invalid pointer\n"?
>> I think "corrupt pointer" doesn't exactly reflect where the bug is.
>
> Ok
>



-- 
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Straße, 33
80636 München

Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg

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  reply	other threads:[~2016-08-02 12:57 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-01 14:45 [PATCH 1/6] mm/kasan: fix corruptions and false positive reports Andrey Ryabinin
2016-08-01 14:45 ` Andrey Ryabinin
2016-08-01 14:45 ` [PATCH 2/6] mm/kasan: don't reduce quarantine in atomic contexts Andrey Ryabinin
2016-08-01 14:45   ` Andrey Ryabinin
2016-08-02 11:42   ` Alexander Potapenko
2016-08-02 11:42     ` Alexander Potapenko
2016-08-01 14:45 ` [PATCH 3/6] mm/kasan, slub: don't disable interrupts when object leaves quarantine Andrey Ryabinin
2016-08-01 14:45   ` Andrey Ryabinin
2016-08-01 14:47   ` Alexander Potapenko
2016-08-01 14:47     ` Alexander Potapenko
2016-08-01 14:45 ` [PATCH 4/6] mm/kasan: get rid of ->alloc_size in struct kasan_alloc_meta Andrey Ryabinin
2016-08-01 14:45   ` Andrey Ryabinin
2016-08-01 14:45 ` [PATCH 5/6] mm/kasan: get rid of ->state " Andrey Ryabinin
2016-08-01 14:45   ` Andrey Ryabinin
2016-08-02 12:37   ` Alexander Potapenko
2016-08-02 12:37     ` Alexander Potapenko
2016-08-01 14:45 ` [PATCH 6/6] kasan: improve double-free reports Andrey Ryabinin
2016-08-01 14:45   ` Andrey Ryabinin
2016-08-02 11:39   ` Alexander Potapenko
2016-08-02 11:39     ` Alexander Potapenko
2016-08-02 12:05     ` Alexander Potapenko
2016-08-02 12:05       ` Alexander Potapenko
2016-08-02 12:34     ` Andrey Ryabinin
2016-08-02 12:34       ` Andrey Ryabinin
2016-08-02 12:53       ` Alexander Potapenko [this message]
2016-08-02 12:53         ` Alexander Potapenko
2016-08-02 16:00     ` [PATCH] kasan-improve-double-free-reports-fix Andrey Ryabinin
2016-08-02 16:00       ` Andrey Ryabinin
2016-08-01 14:45 ` [PATCH 1/6] mm/kasan: fix corruptions and false positive reports Alexander Potapenko
2016-08-01 14:45   ` Alexander Potapenko

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