From: Maciej Wieczor-Retman <m.wieczorretman@pm.me>
To: Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Uladzislau Rezki <urezki@gmail.com>,
Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>,
Alexander Potapenko <glider@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 06/13] mm/execmem: Untag addresses in EXECMEM_ROX related pointer arithmetic
Date: Fri, 23 Jan 2026 09:37:40 +0000 [thread overview]
Message-ID: <aXNBTJzIKeRjQM6O@wieczorr-mobl1.localdomain> (raw)
In-Reply-To: <aXH8wQbyjFqlueNS@kernel.org>
Thanks!
Kind regards
Maciej Wieczór-Retman
On 2026-01-22 at 12:32:33 +0200, Mike Rapoport wrote:
>On Tue, Jan 20, 2026 at 02:41:43PM +0000, Maciej Wieczor-Retman wrote:
>> From: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
>>
>> ARCH_HAS_EXECMEM_ROX was re-enabled in x86 at Linux 6.14 release.
>> vm_reset_perms() calculates range's start and end addresses using min()
>> and max() functions. To do that it compares pointers but, with KASAN
>> software tags mode enabled, some are tagged - addr variable is, while
>> start and end variables aren't. This can cause the wrong address to be
>> chosen and result in various errors in different places.
>>
>> Reset tags in the address used as function argument in min(), max().
>>
>> execmem_cache_add() adds tagged pointers to a maple tree structure,
>> which then are incorrectly compared when walking the tree. That results
>> in different pointers being returned later and page permission violation
>> errors panicking the kernel.
>>
>> Reset tag of the address range inserted into the maple tree inside
>> execmem_vmalloc() which then gets propagated to execmem_cache_add().
>>
>> Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
>> Acked-by: Alexander Potapenko <glider@google.com>
>
>Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
>
>--
>Sincerely yours,
>Mike.
next prev parent reply other threads:[~2026-01-23 9:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 14:40 [PATCH v9 00/13] kasan: x86: arm64: KASAN tag-based mode for x86 Maciej Wieczor-Retman
2026-01-20 14:41 ` [PATCH v9 01/13] kasan: sw_tags: Use arithmetic shift for shadow computation Maciej Wieczor-Retman
2026-01-20 14:41 ` [PATCH v9 02/13] kasan: arm64: x86: Make special tags arch specific Maciej Wieczor-Retman
2026-01-20 14:41 ` [PATCH v9 04/13] x86/kasan: Add arch specific kasan functions Maciej Wieczor-Retman
2026-01-20 14:41 ` [PATCH v9 06/13] mm/execmem: Untag addresses in EXECMEM_ROX related pointer arithmetic Maciej Wieczor-Retman
2026-01-22 10:32 ` Mike Rapoport
2026-01-23 9:37 ` Maciej Wieczor-Retman [this message]
2026-01-20 17:54 ` [PATCH v9 00/13] kasan: x86: arm64: KASAN tag-based mode for x86 Andrey Konovalov
2026-01-20 19:18 ` Maciej Wieczor-Retman
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