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b=YTelDiwaGoABahHhFRpg39hLFeVqNG0gRvpvMSOlFa6Ro+YTDPMUBL+PXbJnEs/fw sm/xbq9pZtxtD7w083cNniZpsn9JoCG222q1Odw2l/cJYs6qDOZj2nxpArKHgtUv8S oaT7yg8MYmwqxdWVW5x8p8MRCHbUJM9Rr/PGBjYNzF8lxDROQBwcO8pkpsOOXxYH6y P1qS9Mu6pRFIFdf3ZwznEE/XkKesrW+NZo67bt3Mx5TGP4wVkHHDT2cxQK5NEiZk2r s2VJu3lUAqtprH5jd1YvMYMB9txR3GomuvgVQDlpe+suH9Ko3R8tDIMyvjCiCa4SP8 QZTGcE0k56c0Q== Message-ID: <682b2569-0a20-4595-b83b-8c833c387baf@kernel.org> Date: Fri, 7 Aug 2026 12:47:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] fork: reset pointer tag of vmapped thread stack before vfree To: sparkhuang Cc: akpm@linux-foundation.org, bsegall@google.com, dietmar.eggemann@arm.com, juri.lelli@redhat.com, kees@kernel.org, kprateek.nayak@amd.com, liam@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, mgorman@suse.de, mhocko@suse.com, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, rppt@kernel.org, ryabinin.a.a@gmail.com, stable@vger.kernel.org, surenb@google.com, vbabka@kernel.org, vincent.guittot@linaro.org, vschneid@redhat.com References: <20260807104153.94261-1-huangshaobo3@xiaomi.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspam-User: X-Stat-Signature: 1etqhjm7r3woz7k5kqbnhjwpgfped44p X-Rspamd-Queue-Id: A7FA4C0006 X-HE-Tag: 1786099689-447172 X-HE-Meta: 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 MScojHrN dtum1lFKPWdyCWnAG10z5wB+0wgSFLEMoI1XBa0owrRj7pZdZFZjji73uhVPScS96VssF+3DX2UqpQ6kVK0bUxRQLc2KJZjby9IMiqe94RI8dGUebm2f4YeCqueduL2rbHbju++9WHFSil/2i0b+mngucQU92SWr7s/i3NQ6wllihuOTNl7ksoY7zqSQriJ3E7GYG6aB2GkSN+eAYWjiJzIFmink5mXAUIRQJ3A5CEQruZa2CK/KnDrIGjZi2TcZ0CoftJQzGxbsxiCwIx0SEER9M8Ag13DlEw4H8ijbE79Hk3+8A1pzq7zXbbcgHhnOb67GvD8RZq2L9t7LjFJaiULICCQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/7/26 12:41, sparkhuang wrote: > On 2026-08-07 9:27 UTC, David wrote: >> Were you able to reproduce this more than once? > > Still trying to reproduce it. So far it has only occurred this once. > >> Does this relate to CONFIG_KASAN_STACK? > > I'm not entirely sure if it's related. > The configs relevant to this path are: > CONFIG_KASAN_SHADOW_OFFSET=0xefffffc000000000 > CONFIG_HAVE_ARCH_KASAN=y > CONFIG_HAVE_ARCH_KASAN_SW_TAGS=y > CONFIG_HAVE_ARCH_KASAN_HW_TAGS=y > CONFIG_HAVE_ARCH_KASAN_VMALLOC=y > CONFIG_CC_HAS_KASAN_GENERIC=y > CONFIG_CC_HAS_KASAN_SW_TAGS=y > CONFIG_KASAN=y > CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX=y > # CONFIG_KASAN_GENERIC is not set > CONFIG_KASAN_SW_TAGS=y > # CONFIG_KASAN_HW_TAGS is not set > CONFIG_KASAN_OUTLINE=y > # CONFIG_KASAN_INLINE is not set > CONFIG_KASAN_STACK=y The KASAN_STACK might be the relevant bit. We will get the stack retagged, so when we free the memory, the stored tag and the memory tag will differ. At least that's my understanding from a quick peek :) -- Cheers, David