From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7A57742C4F0 for ; Tue, 1 Sep 2026 07:23:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788247427; cv=none; b=ZBk6fQBeDUAG2LVcEKPRxkWVEo0NhDTBkps68L/ZQX3C3iwMaVIRoc/Q0TaNVe54vZMkMogE45TnH3+VrbsEKbAL6Tyi+4fXoJsaXDj6PTlWssL9IZWNNyIkbwVckUfQkSMp4Oi+1Jm2B/ZtTCy0RIbelxqLK/Srfr/w9xY8XnI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788247427; c=relaxed/simple; bh=mp7eLHaZfmsO81+U9L/zIi9lOQ3CvFosn62SO4Eqx6I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TFNrHURabP9IdEkAGC7uOYEGzBVhvt5up5G16T6067BmxSiYhsePr7q2651Ki6XOfFWZlfvxmY1LenIccv447eXHhVQs5V9UxB8SlMh2RkX4iKfxmEnNZeSoSNzokdVSu2uZAQ3ykEUP0MjrRq28hYbc6AzLle5PO72JLcTiHJA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=BV0YDgs7; arc=none smtp.client-ip=209.85.128.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="BV0YDgs7" Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-4995b0343c1so44049055e9.3 for ; Tue, 01 Sep 2026 00:23:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1788247424; x=1788852224; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=0niSXQECJMFZw0+rxqv4zMkA2WGEXmXqxfDeDBlDBZ4=; b=BV0YDgs7HFXKsJNwwfMWLV0KQDEQ+fQz8xt9/chXybd87/a9nclqSH1Rb7yhF6tKYu +QVuU/UzTo1UzvNXYkvtzUgkMelOnCa3NXBNR43UhgiLdBHW+rrbqp+RnsoSq1/2E+mi 0pLhwhm64rmHFvR+zyZFflrEjqm/uSWeDF2rwPptj53rJFbDLXRsXWfY8YrAGDnvH/dI 1cdSHoxMmupaz8I9Pd/RzxF3b2vXmu89XY4NYDD63PQHQnu7i3rH6U6a+0gue5/bCyj3 0ow4YUvyri+4k1w4JXBzpPJxF64xhN6pxuQ/EvuGhqUXzDLHeCsf5L0RkfFYDw+OKwxr xdZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788247424; x=1788852224; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=0niSXQECJMFZw0+rxqv4zMkA2WGEXmXqxfDeDBlDBZ4=; b=LOgrSBotP8kCIm3+LkiAP7p2MnjbV/KYWz0HA5htle8AvAkL4pllRqJXGvfArCUDzr rhWFeOKX7TAqMwbqkU2l5BMoOuchU10+IGmDXomnHRlzQedHLkKl+MTcKCYLkoBYiXwH WrbE70jvNMMr9u+o4fPAjn//yz/lFbh8bUEQlSAhx7YIA2dyY4VqNUFIvWaL4n1H3740 Qjm1loe3A8le5GU+yOogFi44MhcZ+QG7a/U7Wnw+RMZvm58dsvwgRuaWhmhcnrzal1GF T3JlEl00rTHUYeg6EOcmFp627jTdM0NQPKCq3e5FKsqT4ikv+0gFZyrABG2byTM5PDGO JE5Q== X-Forwarded-Encrypted: i=1; AHgh+Rrbr7OMSVY6kxhwhTRAvRBM0SeNcTPLAOcSj5XKv8cxQ7MMg5OPAuhlOvu1E9VnQJfsZwVLHJgbBsu2BOs=@vger.kernel.org X-Gm-Message-State: AFuF++mmzOFXp3zElAjQnlHTPnXpTzBcLEXVv67k3G6DDi9ItV8WR004 BGBIA6PoH1YXBjQqwU9OfXBrzXNMu/NmxLPPa0TsFy55epYL1d7vpJpXxLdCIHTzc9w= X-Gm-Gg: AR+sD12fxHJZ2I6Q/vDP2/2I4/kA7a34mOaGh4uN3dj4T46plH637+YvHt1ZiAYPH0i UZk0X/e5kh5h+hg39HubDdYolF+zVdxMfWecO0RWY05xR/zvrr2XIGUW98BB6ns+wRJwT99uPuM NM2bcriyWnAr9G4tgY34lx1fy9qGHFuy7GoQIXKVwLbpTjobLjm3hkbbSzwwHzAWHTb5Y8SAlDR /n1w7qlCxkWWFRj2VGfVNvQbYl15evaANjJ6sX8LnJ8qiXfJWgMDZVTFfbxtL0DYUCg/IL/QodC Kn5TeZfYE7AUXxwZ22uhPeuxSPPiGnyYVKkRgYsom6LAZjfpsXysIMJkblpfPvQOVsviI3NQ8kt 7q9es82uGT0Or3HXgv49FhgJYC+HacGNfpiGmWS/gm1YdUmUA+XMAvrlY+uMbTObVh6J7fq1ZJH c/YnDPvT03ezfGo+ZVk0ug961yRnitzP9mk4DeCzWvfxf9jTB4e0gE5vVkhEypUw== X-Received: by 2002:a05:600c:45d4:b0:499:7219:122f with SMTP id 5b1f17b1804b1-49b91c1ebd7mr438451325e9.4.1788247423615; Tue, 01 Sep 2026 00:23:43 -0700 (PDT) Received: from pathway.suse.cz ([176.114.240.130]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49b91c52fdbsm254947765e9.0.2026.09.01.00.23.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2026 00:23:41 -0700 (PDT) Date: Tue, 1 Sep 2026 09:23:37 +0200 From: Petr Mladek To: Steven Rostedt Cc: Sebastian Andrzej Siewior , Thomas Gleixner , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Andrew Morton , Andy Shevchenko , Kees Cook , Rasmus Villemoes , Sergey Senozhatsky , Tycho Andersen , Linus Torvalds Subject: Re: [PATCH v2 2/2] kallsyms: Document why unresolved symbols are revealed Message-ID: References: <20260821152614.2202196-1-bigeasy@linutronix.de> <20260821152614.2202196-3-bigeasy@linutronix.de> <20260827102411.NsziRXyJ@linutronix.de> <20260831133729.p5ylO7O6@linutronix.de> <20260831124928.22e163ab@gandalf.local.home> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260831124928.22e163ab@gandalf.local.home> On Mon 2026-08-31 12:49:28, Steven Rostedt wrote: > On Mon, 31 Aug 2026 15:37:29 +0200 > Sebastian Andrzej Siewior wrote: > > > Could someone yell here, please? I convinced myself that hiding > > unresolved pointers is the good thing to do here since a "wrong" pointer > > would be seen in backtrace anyway. > > > > Thread starts at > > https://lore.kernel.org/all/20260821152614.2202196-1-bigeasy@linutronix.de/ > > I wonder if we should just tagged hash values as such: > > | [ 1.498171] > | [ 1.498172] 00000000cb9bc262 [hash] > | [ 1.498174] ? 00000000eb5021dd [hash] > | [ 1.498176] 00000000ed1a9938 [hash] > | [ 1.498178] > > So that people will know that the value is just some random hash value and > not a real address. > > Although rather useless in call stacks, I like hash values because the same > address will show up the same. > > Having '[unknown]' may also be confusing because it doesn't really say > "why" it was unknown. But having a number goes back to what it always did. > Hashing it with a "[hash]" marker will also let people know the value was > hashed. I like this idea. I just wonder whether it might confuse some parsers who expect that symbol name is one string. %ps, %pS, %pB are used in various context. I think about adding the hint into the hashed value, e.g. by using 'h' instead of the highest number, something like: [ 1.498171] [ 1.498172] h0000000cb9bc262 [ 1.498174] ? h0000000eb5021dd [ 1.498176] h0000000ed1a9938 [ 1.498178] But 'h' is not a valid number number so it might confuse parsers as well. And it is not that user friedly either. So, I still like more Steven's variant with [hash]. Best Regards, Petr