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X-CSE-ConnectionGUID: 9yeX7kfpRciTK31HJ6vEeA== X-CSE-MsgGUID: irLq5cuISV+K+MbdeRzUZw== X-IronPort-AV: E=McAfee;i="6800,10657,11535"; a="58654379" X-IronPort-AV: E=Sophos;i="6.18,214,1751266800"; d="scan'208";a="58654379" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Aug 2025 07:36:58 -0700 X-CSE-ConnectionGUID: oAhQu6z0QzWaUhrAy9v3yg== X-CSE-MsgGUID: WbFDIWzsSLWxVqB0FRAlOw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,214,1751266800"; d="scan'208";a="170680834" Received: from dwesterg-mobl1.amr.corp.intel.com (HELO [10.125.109.56]) ([10.125.109.56]) by fmviesa010-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Aug 2025 07:36:57 -0700 Message-ID: <99878868-9898-46aa-ad4c-ef9aca3e390c@intel.com> Date: Wed, 27 Aug 2025 07:36:56 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH -next] x86: Prevent KASAN false positive warnings in __show_regs() To: Tengda Wu , x86@kernel.org Cc: Andrey Ryabinin , Thomas Gleixner , Alexander Potapenko , Andrey Konovalov , Borislav Petkov , Dave Hansen , Dmitry Vyukov , Ingo Molnar , linux-kernel@vger.kernel.org, Peter Zijlstra , Josh Poimboeuf References: <20250818130715.2904264-1-wutengda@huaweicloud.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/18/25 06:07, Tengda Wu wrote: > +__no_sanitize_address > void __show_regs(struct pt_regs *regs, enum show_regs_mode mode, > const char *log_lvl) I'd feel a lot better about this if it didn't just disable KASAN for the whole function. Surely there are other __show_regs() users that could benefit from sanitizer coverage. Can we limit the impact to just the asynchronous (unsafe) stack walkers? If it's just for sysrq, this seems like the kind of thing we could just a flag somewhere and have KASAN suppress the warning. Or to generically tell KASAN that we might be doing accesses in a certain memory range that are unsafe. I'm also adding Peter and Josh to cc. Seems like the kind of thing they might have an opinion on.