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From: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
To: Andrey Konovalov <andreyknvl@gmail.com>
Cc: <kees@kernel.org>, <julian.stecklina@cyberus-technology.de>,
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Subject: Re: [PATCH v2 01/14] kasan: sw_tags: Use arithmetic shift for shadow computation
Date: Tue, 4 Mar 2025 13:29:34 +0100	[thread overview]
Message-ID: <aanh34t7p34xwjc757rzzwraewni54a6xx45q26tljs4crnzbb@s2shobk74gtj> (raw)
In-Reply-To: <CA+fCnZcCCXPmeEQw0cyQt7MLchMiMvzfZj=g-95UOURT4xK9KQ@mail.gmail.com>

On 2025-03-01 at 01:22:46 +0100, Andrey Konovalov wrote:
>On Thu, Feb 27, 2025 at 1:33 PM Maciej Wieczor-Retman
><maciej.wieczor-retman@intel.com> wrote:
>>
>> Btw just out of curiosity on the topic. If we used a runtime specified kasan
>> offset, could the gdb script issue (not knowing the offset at compile-time) be
>> fixed by just exporting the value through sysfs?
>>
>> I know that in inline mode the compiler would still need to know the offset
>> value but I was curious if this approach was okay at least in outline mode?
>
>I think this would work, assuming that GDB can pick it up from sysfs.

One other question that came to me about how KASAN works, is there some
mechanism to prevent data races between two threads? In the compiler perhaps?

For example memory is de-allocated and shadow memory is poisoned but some other
thread was just about to do a shadow memory check and was interrupted?

I've read the kasan/vmalloc.c comments and from them I'd extrapolate that the
caller needs to make sure there are not data races / memory barriers are in
place.

-- 
Kind regards
Maciej Wieczór-Retman


  reply	other threads:[~2025-03-04 12:31 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-18  8:15 [PATCH v2 00/14] kasan: x86: arm64: KASAN tag-based mode for x86 Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 01/14] kasan: sw_tags: Use arithmetic shift for shadow computation Maciej Wieczor-Retman
2025-02-19 23:29   ` Andrey Konovalov
2025-02-21 13:11     ` Maciej Wieczor-Retman
2025-02-22 15:06       ` Andrey Konovalov
2025-02-25 17:20         ` Maciej Wieczor-Retman
2025-02-25 19:12           ` Maciej Wieczor-Retman
2025-02-25 20:12             ` Maciej Wieczor-Retman
2025-02-25 21:38               ` Andrey Konovalov
2025-02-26 16:42                 ` Maciej Wieczor-Retman
2025-02-26 19:44                   ` Andrey Konovalov
2025-02-27 12:27                     ` Maciej Wieczor-Retman
2025-02-28 16:12                       ` Maciej Wieczor-Retman
2025-03-01  0:21                         ` Andrey Konovalov
2025-03-04 14:06                           ` Maciej Wieczor-Retman
2025-03-07  1:10                             ` Andrey Konovalov
2025-03-13 14:56                               ` Maciej Wieczor-Retman
2025-03-18 15:31                                 ` Andrey Konovalov
2025-02-25 21:37           ` Andrey Konovalov
2025-02-27 12:33             ` Maciej Wieczor-Retman
2025-03-01  0:22               ` Andrey Konovalov
2025-03-04 12:29                 ` Maciej Wieczor-Retman [this message]
2025-03-07  1:10                   ` Andrey Konovalov
2025-03-14 15:57                     ` Maciej Wieczor-Retman
2025-03-18 15:32                       ` Andrey Konovalov
2025-02-18  8:15 ` [PATCH v2 02/14] kasan: sw_tags: Check kasan_flag_enabled at runtime Maciej Wieczor-Retman
2025-02-19 23:30   ` Andrey Konovalov
2025-02-21 14:35     ` Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 03/14] kasan: sw_tags: Support outline stack tag generation Maciej Wieczor-Retman
2025-02-19 23:30   ` Andrey Konovalov
2025-02-18  8:15 ` [PATCH v2 04/14] kasan: sw_tags: Support tag widths less than 8 bits Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 05/14] kasan: arm64: x86: Make special tags arch specific Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 06/14] x86: Add arch specific kasan functions Maciej Wieczor-Retman
2025-02-19 23:30   ` Andrey Konovalov
2025-02-21  8:40     ` Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 07/14] x86: Reset tag for virtual to physical address conversions Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 08/14] x86: Physical address comparisons in fill_p*d/pte Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 09/14] mm: Pcpu chunk address tag reset Maciej Wieczor-Retman
2025-03-20 17:39   ` Andrey Ryabinin
2025-03-20 17:47     ` Andrey Konovalov
2025-03-21 10:40     ` Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 10/14] x86: KASAN raw shadow memory PTE init Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 11/14] x86: LAM initialization Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 12/14] x86: Minimal SLAB alignment Maciej Wieczor-Retman
2025-02-19 23:30   ` Andrey Konovalov
2025-02-21  7:24     ` Maciej Wieczor-Retman
2025-02-18  8:15 ` [PATCH v2 13/14] x86: runtime_const used for KASAN_SHADOW_END Maciej Wieczor-Retman
2025-02-19 23:31   ` Andrey Konovalov
2025-02-21 15:10     ` Maciej Wieczor-Retman
2025-02-21 15:27       ` Maciej Wieczor-Retman
2025-02-22 15:08         ` Andrey Konovalov
2025-02-22 15:07       ` Andrey Konovalov
2025-02-25 17:15         ` Maciej Wieczor-Retman
2025-02-25 21:37           ` Andrey Konovalov
2025-02-26 11:52             ` Maciej Wieczor-Retman
2025-02-26 15:24               ` Andrey Konovalov
2025-02-26 17:03                 ` Maciej Wieczor-Retman
2025-03-21 19:20                 ` Maciej Wieczor-Retman
2025-03-21 20:16                   ` Andrey Konovalov
2025-03-24 10:43                     ` Maciej Wieczor-Retman
2025-03-24 10:50                       ` Maciej Wieczor-Retman
2025-03-24 21:58                         ` Andrey Konovalov
2025-02-18  8:15 ` [PATCH v2 14/14] x86: Make software tag-based kasan available Maciej Wieczor-Retman
2025-02-19 23:31   ` Andrey Konovalov
2025-02-20 16:32     ` Andrey Konovalov
2025-02-21 14:44     ` Maciej Wieczor-Retman
2025-02-22 15:06       ` Andrey Konovalov
2025-02-25 15:39         ` Maciej Wieczor-Retman
2025-02-20  2:49   ` kernel test robot

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