From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f46.google.com (mail-wr1-f46.google.com [209.85.221.46]) (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 C5F5F3EF0C0 for ; Thu, 23 Apr 2026 13:06:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776949578; cv=none; b=ZR1xbRdvRhkECt7eNRy7im2055/2ThzBavJwIDn+n9gHIDXYdQZQBb/KCzJ2GumUGLyfclVk1Pwq+XCUBnGsmj490OM4Y2G/43tEeAZIQy0+fnwP0Fj9ocGdl60sUuogbmSLZ2GnQ6/fvh6hTA4sNUN10gdtFbzj3IEbrIK+YOo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776949578; c=relaxed/simple; bh=a07u/h/DFxnIT8CA8KZAmxUm47K/feDZx0GWQAH24U0=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uiS8F1mj+4Ej40t8R7lAzQ+tFclXfXPpzUNRzPX/456sxrQij1U+pK1/osuLPEJXSgZ5Dg3pWsaXcGFJ86laCQsGJd4QCZ1cBXjVfDMoxGgUCnePCxV5WVBq24hyPgazFNmVHMu5XP5aTv6bATr9qvx9J3vCpy8fX7TKVdT8l2k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=gn19dfiq; arc=none smtp.client-ip=209.85.221.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gn19dfiq" Received: by mail-wr1-f46.google.com with SMTP id ffacd0b85a97d-43cff5dafc3so5393940f8f.1 for ; Thu, 23 Apr 2026 06:06:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776949575; x=1777554375; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=7W6wCJvvd3w5bemRCbvVqU4AXXtyRVKRO3lOAIo4u64=; b=gn19dfiq3iQhVAu4KMLwRgHQxfh6GTZ7uFzjHvTITl2bXoHYsldeRK4tpU+C0wgkYj k5tYQHjim1x1xMP3mg1BcsSNEM92PTdCe7f5iWykLCarb4ba3l+6gMDz5TNQpGA62d6m JWrlgHc0ImfWV+K+m214yE4vNAA9YcqO5w61Quk8JuPyD0rmC08Ae48JvJQRugd/yzVy IjQuFZcwAvgLSMmQRqMIfilo7C4bACvnGQ4UDaPVrD/mPCkYOrvKX6Mvz59jQ3FRKBT0 K7WOSCCsD/bFVpxAappijE8yWJlN5FSRTzVEPOpGXY2FAWfSosfsT2uRtwl0kFy0b7Qt ZRhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776949575; x=1777554375; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=7W6wCJvvd3w5bemRCbvVqU4AXXtyRVKRO3lOAIo4u64=; b=SqTKvI/R6n34qJlFNZUNiz+33YTgZalWONhbjU6UVoaXspmevXbHmDjFT4inOBisdG Q1qHiMjwSETpvn+gHDeJLGukNT896M+EAaDuJBdkBysZ0+yYDbI1HhWVquYy9B+eKcZB FXNX0Js7lgWNqGNbHpBiit8omwKzSv4uDt5hOExV0t+FC2Le3fGGgqOUtk8DfQYU3GTX ujT1SMHjFPaPANtkHEKED3knLAhZKxq+ACkDKeEfjRypoaRft69WdbshIzTnmydxs0ZK HLKyU1AUSjvFcOtc9KL1nW63ZLx6zODYD62Qw3KbxzLj1zE+Shc6tOhXyUsf0SLzi83H 6cJQ== X-Forwarded-Encrypted: i=1; AFNElJ/0Jv48mXDl3yhO80xlNQTTFjdCzJqmQikMGfcKzw7K2F9kEqbV50VE2WZN+Tk5sKE30P4v0A==@lists.linux.dev X-Gm-Message-State: AOJu0YzgqU7Kf3cgtKvwsyqdqUmIn+UxbtGOx2gBAasFBuaaFBkkzKIe Uuhd8XtUs6S5T5Lsgo3zlrNwOS0sn2ZzQcPEORwuBnXgsV/fwMWCqxE3 X-Gm-Gg: AeBDievpI8E72nH8YJQyQaoetCZdLjoXfdRs7yfUy8mallhr1+97SFhdfnnw6J+XutA Sh/SIReF30YSue41H5X7lLV8cfTjz6hj6BU9VM2zU+7lMlpNwRFWqOpYHBs9+qydyCmQ4NcrabS v4e8hNH0K+dawBT/g3P/g5N/22v9rqPjkpa6yy0Pbz/mcNsaEaNjNs8C0G+mom+Rm/eob/u3zMw xE+obgKLlteOAVPzyaOBAGN0oIDTswmdcuCpnjgA6T2PANAzO7LffPEpxEDjkFq9uBmjZzfSFGS 8z1DuxsAbn8P0dIKzlbtKcaxmyqwJeAWmsxnrZHdUawbpElwNLflsRD9uelv2x37M90PBxSAoDk goQdR1EwX5q0FXUTV3oVH8W7VsgLSnE9lLZgbG7in1IN3ZZp2r1Ma2bB6BwT//cc7U+vuCRvBbq J727wiC1Viv1xHwG5TwMF1ZFDaLC77Z+WG3qZTUJl69DJ0Oa7+kbwVJjmt7aSULEg1nsi0n/HdZ tc= X-Received: by 2002:a05:6000:2902:b0:439:b8b2:fad0 with SMTP id ffacd0b85a97d-43fe3dc81a7mr42752149f8f.5.1776949575075; Thu, 23 Apr 2026 06:06:15 -0700 (PDT) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43fe4cb1176sm54479709f8f.3.2026.04.23.06.06.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Apr 2026 06:06:14 -0700 (PDT) Date: Thu, 23 Apr 2026 14:06:12 +0100 From: David Laight To: Marco Elver Cc: Arnd Bergmann , Konstantin Komarov , Dmitry Vyukov , ntfs3@lists.linux.dev, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: Re: kcsan -Wmaybe-uninitialized warning in ntfs3 Message-ID: <20260423140612.46df8b78@pumpkin> In-Reply-To: References: <5da10cca-875b-418d-b54e-6be3ea32c266@app.fastmail.com> <28064669-bb57-4dab-bac5-cc1027bafaa3@app.fastmail.com> <0df31031-23d4-49cf-8643-f605561bf7fb@app.fastmail.com> <6eac698f-da35-4efc-b227-b54de5d1decb@app.fastmail.com> <49780769-461a-4a09-a7df-c34a2e839e45@app.fastmail.com> <4b36f629-9338-40e0-b114-ee37aaad9cf3@app.fastmail.com> <20260423091246.7ffa38c4@pumpkin> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: ntfs3@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 23 Apr 2026 13:35:09 +0200 Marco Elver wrote: > On Thu, 23 Apr 2026 at 10:12, David Laight wrote: > > On Wed, 22 Apr 2026 23:50:22 +0200 > > Marco Elver wrote: > > > > > Which means the simplest fix is probably the absolute_pointer() one. > > > > I'm not sure that using absolute_pointer() is right, it is normally used > > for special conversions in low level boot code. > > > > Here it might just be best to explicitly use (void *)(long)addr. > > That didn't work - tried, and warnings still there (GCC seems to see > through it). The only difference is the extra local - unless the '+ 0' matters. OPTIMIZE_HIDE_VAR() should work, but is annoying to use in a function call. You sort of need: #define OPTIMIZER_HIDE_VAL(x) {( \ auto _x = x; \ asm ("", "+r" (_x)); \ _x; \ )} (also useful for 'lying' to snprintf()) David > > So that leaves: > - absolute_pointer() > - __diag_ignore_all wrapper (mentioned elsewhere in thread) > > Preferences? > > Thanks, > -- Marco