From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 ACAB428F3; Wed, 26 Feb 2025 15:59:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740585595; cv=none; b=hwUJk6OKHoyfFZdPEmQdlYGW0Ta3FJZEQxZ1OdGDHzmhiGuwyh7lTr3AG2xTeiuEhGe7ENS9n4AOLnHHcPc6ocQ8LgB+CBrhGfW+cucKdJHDLhRVjoGoTlIfHtOGaE9AVodOyRMrSJhD6XzpGw+3/WyoO+zV3ismjF2E7MF89bE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740585595; c=relaxed/simple; bh=8U3HqDiHPY2xjpZ1i9Tfu5CN8cLyRtEgus9/9JMgOvU=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=H9NqH8fRTuVlHKYrvBItzto3Eja7jVvJNpk2l2dec7WnNt1JgA0mX4D0ebbJ+3dhHEvVEH/T/YEhwSjnWo4FRKmRzNw16FK6wLc64LjfY2PQABBQKAXF5byDnYM2zERs0PW7A9Ny1KEtA9EM/xpQtJIMEW54tLa3FagsihJGogE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AB04C4CEE8; Wed, 26 Feb 2025 15:59:53 +0000 (UTC) Date: Wed, 26 Feb 2025 11:00:33 -0500 From: Steven Rostedt To: James Bottomley Cc: Greg KH , Miguel Ojeda , Ventura Jack , Kent Overstreet , "H. Peter Anvin" , Alice Ryhl , Linus Torvalds , Gary Guo , airlied@gmail.com, boqun.feng@gmail.com, david.laight.linux@gmail.com, ej@inai.de, hch@infradead.org, ksummit@lists.linux.dev, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Ralf Jung Subject: Re: C aggregate passing (Rust kernel policy) Message-ID: <20250226110033.53508cbf@gandalf.local.home> In-Reply-To: <16127450a24e9df8112a347fe5f6df9c9cca2926.camel@HansenPartnership.com> References: <5E3FEDC4-DBE3-45C7-A331-DAADD3E7EB42@zytor.com> <2rrp3fmznibxyg3ocvsfasfnpwfp2skhf4x7ihrnvm72lemykf@lwp2jkdbwqgm> <2025022611-work-sandal-2759@gregkh> <16127450a24e9df8112a347fe5f6df9c9cca2926.camel@HansenPartnership.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: ksummit@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 Wed, 26 Feb 2025 09:45:53 -0500 James Bottomley wrote: > >From some other rust boot system work, I know that the quality of a > simple backtrace in rust where you just pick out addresses you think > you know in the stack and print them as symbols can sometimes be rather > misleading, which is why you need an unwinder to tell you exactly what > happened. One thing I learned at GNU Cauldron last year is that the kernel folks use the term "unwinding" incorrectly. Unwinding to the compiler folks mean having full access to all the frames and variables and what not for all the previous functions. What the kernel calls "unwinding" the compiler folks call "stack walking". That's a much easier task than doing an unwinding, and that is usually all we need when something crashes. That may be the confusion here. -- Steve