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b=GopdvMk22g+PZk/+/gUQU104GzpyK2EYIiA29AMbxC2zw/km9FvXh2j6Wwf+5R7EU GVJrokrOqoyf3QR+LRdBhzHYw3dPOIhQNC7/p8/dE7D9Mi104IHeY60jxfIDeh13Dr Ig+dNeto7UTGbRxsfgvwVELVyV9QZL4HO4/Cmr3Bpv/3G8fOu9pBOF3r3jBQkdPa2v 3BU/s7RNByAuVom5DcJG9fOYkurclVkanfm0pYRZ0vY8llNN/zotKZkINO2Qdv6mHG Wkn51FhVSxbxkLI6qCah1VxDfNUwlAMCHy9Ha68mAB7cNdF2MOhnja04L79Fe2mENi WqcVLIaxCP2vg== Date: Thu, 22 Jan 2026 12:32:33 +0200 From: Mike Rapoport To: Maciej Wieczor-Retman Cc: Andrew Morton , Uladzislau Rezki , Maciej Wieczor-Retman , Alexander Potapenko , 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 Message-ID: References: <50701245bae3d2c543f518d206539ba71367075c.1768845098.git.m.wieczorretman@pm.me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50701245bae3d2c543f518d206539ba71367075c.1768845098.git.m.wieczorretman@pm.me> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 017D62000B X-Stat-Signature: p7iukaqjcxs4u5tqkf1b71omxakztusg X-HE-Tag: 1769077960-279847 X-HE-Meta: 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 Pofh/VsB oSRSm1pqjcJAadScqWEZ2wie+2Xy3ZsbwEeEhWyuufOc/BAllE5c3M4jkkm3FcXMG0lLIGcH3PTspPABGqDvEmadYkIoI2FwBOsL1bLsyRsC5ivxanepKScjDEgwH9SvzDfEaOP8R4ONWyt0alEuoEaekBY/il/QmC8qFZgTHVxUFyEfYNiSynBls1jrENDyVqmwYBcvgv4Al70Skc+0wTTpyu0kdpFQW3VXVG2Z1q+Yl9I6aqRZy6hdgqkiNVne9XvRBOChoIK89YwXmP+fanFyjFggZL+tvtYm8T04rfL/HZ5vp4YaBC1j+vmhDq/xWTBLkxm+zLBX2chnYOYmggPmKHk5no+SyE6nK55VUV5X0XdTSUJYFfvLV7Q== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jan 20, 2026 at 02:41:43PM +0000, Maciej Wieczor-Retman wrote: > From: Maciej Wieczor-Retman > > 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 > Acked-by: Alexander Potapenko Acked-by: Mike Rapoport (Microsoft) -- Sincerely yours, Mike.