From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1254C83F13 for ; Sat, 26 Aug 2023 22:01:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229919AbjHZWAB (ORCPT ); Sat, 26 Aug 2023 18:00:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229748AbjHZV77 (ORCPT ); Sat, 26 Aug 2023 17:59:59 -0400 Received: from mail-qk1-x72c.google.com (mail-qk1-x72c.google.com [IPv6:2607:f8b0:4864:20::72c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01539BA for ; Sat, 26 Aug 2023 14:59:57 -0700 (PDT) Received: by mail-qk1-x72c.google.com with SMTP id af79cd13be357-76ef03f76c7so130264585a.3 for ; Sat, 26 Aug 2023 14:59:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1693087196; x=1693691996; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=+d25/oRbe7pZrMK6QS9SWtlopgnx8v3V9t4b19GIo6E=; b=BtTLFOJhRnTuSw6G2e2ogPuq4gOQaZ3mCHQgwYxJdo2IoSPus4cHtKoBmCpxBfWoHo nOud02qlUoGqj5ezB8fY04yGRhiwpGbz3aG5vta/vjpK6NOvFR7iRMeUgVWI19/x6xo4 vVpj8vNyQbx5NkXT2dmqdW3xplomNR0vj+yWYZnvPIQUddS/HQpjv+Q3U/ZLPaHtb4IB i6z4lsKteZ8sYkyNIOhdwlpVaslJSo77FfmHzweI9YGqmgC4VLDWC6npqTPkE3Nrrivr AxcfdioZW9zZYhmGgUbyQ5YkZDduflhOmp0SGjl/1a1eO9NZn+a/k3pjNNF1JXoot+kD Wh/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693087196; x=1693691996; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=+d25/oRbe7pZrMK6QS9SWtlopgnx8v3V9t4b19GIo6E=; b=G/snLsmd7qlMBwlNEf79OZAh+1ghlOKFy/OUF/zTQsDvmpjpdjowyPH7vas1l96q72 DL+uJKfqbgp0icyBT8SL55tSPnUaGu9LzaCZyh//xrHTn0EAhyC7fCo6h0tNhrZiqNW9 uP38cx58dIAo6yLSqpjVOtVosPxS9HlEB7igZFcxaZUKXm8A1yRAbq7WjXLqvkfHI4QU nHccWdWgmafWwsCmcwtVuN3SPx0L4I5jJYVmDtFliwj6bB+U2wHDesTAJDwaVXzGy3kn kBKl47UqhA3uPPWfNG/CS+MEHjDQkcXdoOobhWl6WWEycV1vEFUf9jl1New30Ml7CWTQ KgdQ== X-Gm-Message-State: AOJu0YxmxQzl+KoaCFO29NWa/EOJafebdptUvyfxTLyDhVbCGOxRq0ua A2hJ8EPpqojo4JM2LV4yvk07vrjmWQu6S0iTmOR31xHGZpc= X-Google-Smtp-Source: AGHT+IEg8o0YHljsGZjksD8nA+PUfXO8XlEI/BvZxU7fVwkrfPXKu7KjivzVjSgOUKFt4fIqmyGfjKAb7lLaMOn5Cr8= X-Received: by 2002:a05:620a:410b:b0:76e:e68d:149b with SMTP id j11-20020a05620a410b00b0076ee68d149bmr13223021qko.50.1693087195923; Sat, 26 Aug 2023 14:59:55 -0700 (PDT) MIME-Version: 1.0 From: Joshua Hudson Date: Sat, 26 Aug 2023 14:59:45 -0700 Message-ID: Subject: Cache coherency bug: stale reads on /dev/sda1 To: linux-kernel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org uname -a Linux nova 6.4.12 #1 SMP PREEMPT_DYNAMIC Sat Aug 26 09:11:27 PDT 2023 x86_64 GNU/Linux Kernel source is https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/linux-6.4.12.tar.xz Can reliably reproduce as follows: # hexedit /dev/sda1 (this is my EFI partition) PgDn # hexedit /dev/sda G 100000 (your value may vary--we want to seek to the start of the EFI partition) PgDn PgDn ^C write a marker to the padding between the BPB and the first FAT sector. (If your system doesn't have one, edit an error message in the boot sector) ^X # hexedit /dev/sda1 PgDn Look for marker written above, find it's not there !!! ^C I discovered this one trying to defragment my EFI partition after a grub upgrade left it very fragmented due to replacing logos.