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From: Andrey Konovalov <andreyknvl@gmail.com>
To: Marco Elver <elver@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Potapenko <glider@google.com>,
	 Dmitry Vyukov <dvyukov@google.com>,
	Taras Madan <tarasmadan@google.com>,
	 Aleksandr Nogikh <nogikh@google.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	 Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Jonathan Corbet <corbet@lwn.net>,
	kasan-dev@googlegroups.com,  linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] kasan: add support for kasan.fault=panic_on_write
Date: Tue, 20 Jun 2023 12:57:39 +0200	[thread overview]
Message-ID: <CA+fCnZdy4TmMacvsPkoenCynUYsyKZ+kU1fx7cDpbh_6=cEPAQ@mail.gmail.com> (raw)
In-Reply-To: <20230614095158.1133673-1-elver@google.com>

On Wed, Jun 14, 2023 at 11:52 AM Marco Elver <elver@google.com> wrote:
>
> @@ -597,7 +614,11 @@ void kasan_report_async(void)
>         pr_err("Asynchronous fault: no details available\n");
>         pr_err("\n");
>         dump_stack_lvl(KERN_ERR);
> -       end_report(&flags, NULL);
> +       /*
> +        * Conservatively set is_write=true, because no details are available.
> +        * In this mode, kasan.fault=panic_on_write is like kasan.fault=panic.
> +        */
> +       end_report(&flags, NULL, true);

Hi Marco,

When asymm mode is enabled, kasan_report_async should only be called
for read accesses. I think we could check the mode and panic
accordingly.

Please also update the documentation to describe the flag behavior wrt
async/asymm modes.

On a related note, it looks like we have a typo in KASAN
documentation: it states that asymm mode detects reads synchronously,
and writes - asynchronously. Should be the reverse.

Thanks!


  parent reply	other threads:[~2023-06-20 10:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-14  9:51 Marco Elver
2023-06-14 10:06 ` Alexander Potapenko
2023-06-20 10:57 ` Andrey Konovalov [this message]
2023-06-20 11:32   ` Marco Elver
2023-06-20 11:45     ` Andrey Konovalov
2023-06-20 11:51       ` Marco Elver
2023-06-20 13:56         ` Andrey Konovalov
2023-06-20 14:48           ` Marco Elver
2023-06-20 16:27             ` Andrey Konovalov
2023-06-20 17:17               ` [PATCH] kasan, doc: note kasan.fault=panic_on_write behaviour for async modes Marco Elver
2023-06-20 17:19                 ` Andrey Konovalov
2023-06-20 17:23               ` [PATCH] kasan: add support for kasan.fault=panic_on_write Marco Elver

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