From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 11E7218E1D for ; Sun, 14 Apr 2024 02:05:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=18.9.28.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713060343; cv=none; b=OF8a/q3EhB1wypN3KCQyYfX//v1hvXAkg8dVSqFL2Tl4XEof0mWArFy+4xhDAH4MhqhkgI12wegm7bnbO5NvxBDF7fg0Qjad8QCchMU5Dg2MW0pB+xM97mAZ9uzwZdt0cbvV9y3G/HUu2+7DAxaa3xzzLWnSTqwHYXzDq7WGaVM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713060343; c=relaxed/simple; bh=MGA7H4Ak7JA9w5IRIFq0xzZptOoFSfbXSg3Cr7bmVbI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HPQJqjxZ60YXY1m0iGXKqDTGD8gXTsNdNXTjELewTRTXFex4osa1cFlipaxY7m+QC+nKeMTl7gsCfIwsDoKAycyEMJo3S1sz2wsx1okUcfuaWKiqqDgoXijR4wvGGEgPtRyMwcNQB2KFXEjVU5CxcQhIAn0MQ13yNVi2wwth228= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu; spf=pass smtp.mailfrom=mit.edu; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b=gm3P5WlG; arc=none smtp.client-ip=18.9.28.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mit.edu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b="gm3P5WlG" Received: from cwcc.thunk.org (pool-173-48-113-2.bstnma.fios.verizon.net [173.48.113.2]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 43E24vOI017915 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 13 Apr 2024 22:04:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1713060302; bh=FXSMfOuJHvgzP8fvH4L0dhdvcbQaONOy8jw0JVIAXwY=; h=Date:From:Subject:Message-ID:MIME-Version:Content-Type; b=gm3P5WlGyVoxRXP+9V0+YSIDP2kbuJVkylgPM0ppChEX+mShuq2ApJQwm4LJi6JiM XAJeqmaIk2fkUcSKpL5sWI34RcX4YiBVnM2qqJzYkvx1p01d140S7MzfDGW7YQLv4u b/xa4LsfcgXuHrl0IBj0V429c2XtwgobI2g5ZaW/RhJnQX/Xv9HtIJPA+ufw+oCj61 +DWfJqm/U35Fiq3YmCB0hMqHTg4BhpKBzLGjUVLkAG8c3iX1XTNM7TTSSfs1NqvRlN QtwqUZmHuek5X6bCtWIveyFW45QyozNCugTcV7FKP8v9Z5Sw93aWz3tm0ooVa1xX5U z8YFtBqJbxLAw== Received: by cwcc.thunk.org (Postfix, from userid 15806) id 8F3FD15C0CB5; Sat, 13 Apr 2024 22:04:57 -0400 (EDT) Date: Sat, 13 Apr 2024 22:04:57 -0400 From: "Theodore Ts'o" To: Andreas Dilger Cc: Nam Cao , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , linux-fsdevel , Alexander Viro , Christian Brauner , Jan Kara , Linux Kernel Mailing List , linux-riscv@lists.infradead.org, Ext4 Developers List , Conor Dooley Subject: Re: riscv32 EXT4 splat, 6.8 regression? Message-ID: <20240414020457.GI187181@mit.edu> References: <878r1ibpdn.fsf@all.your.base.are.belong.to.us> <20240413164318.7260c5ef@namcao> <22E65CA5-A2C0-44A3-AB01-7514916A18FC@dilger.ca> Precedence: bulk X-Mailing-List: linux-ext4@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: <22E65CA5-A2C0-44A3-AB01-7514916A18FC@dilger.ca> On Sat, Apr 13, 2024 at 07:46:03PM -0600, Andreas Dilger wrote: > This looks like a straight-forward mathematical substitution of "dlimit" > with "search_buf + buf_size" and rearranging of the terms to make the > while loop offset "zero based" rather than "address based" and would > avoid overflow if "search_buf" was within one 4kB block of overflow: > > dlimit = search_buf + buf_size = 0xfffff000 + 0x1000 = 0x00000000 Umm... maybe, but does riscv32 actually have a memory map where a kernel page would actually have an address in high memory like that? That seems.... unusual. If we have a reliable reproduction, can someone actually printk the address or test to see if this theory is correct? - Ted