From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (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 4BCE5221F26 for ; Wed, 26 Feb 2025 14:45:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740581158; cv=none; b=jAoDLfkYbA2P2kc3UYxPAHdcdeuRpZhTMANdUEyms18KrTWWN7rgA+yL1nNb+vAoAD/QiQbWfE1lK4Kp5hdl1yuv+fYkKF9ZGsFx+sSmfQsx67cIFXNLJOenFn2TQ+k5SLNqshbMHnIopRJj78Wh6ZJp38IjqkrfFQOFgZYVbYk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740581158; c=relaxed/simple; bh=yYTySIEW2vyb9fQfSiWDrhePMMoxgZdjZmmJCBzHfiY=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=l1U6WW/+vGmGarr9Y7c0o9/JfxKsYHjgm4CxAtw6X8/DQE7MHH7O13NFF5azsooLQf4prHvAf2wFo6lcU7DhTWKpVQ3Lu7tDkzyU6AZDTS7piEPr4TM0G9YYYvKoqkyXHVUASvS//6S3BFtuwqkw/QNAITX09Ki5OJtoNsTPXBE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com; spf=pass smtp.mailfrom=HansenPartnership.com; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b=w9uE/21M; arc=none smtp.client-ip=198.37.111.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="w9uE/21M" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1740581155; bh=yYTySIEW2vyb9fQfSiWDrhePMMoxgZdjZmmJCBzHfiY=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=w9uE/21MKYo/CoH4yc5VHQq6YGVeHHWbTNNKbhNNdrX9KqyIy/wXk0Uyklhy75xJ/ iB4lyacb/CYp0iZkOFcg/HD/X3vWJ/fRK68u/yagIywyDmIYKdkM/LvKouBw+AYcgO 7Q8t1o6+jr69ac9BOgdqOVJ8T/veh8YMlNsjcd6A= Received: from lingrow.int.hansenpartnership.com (unknown [IPv6:2601:5c4:4302:c21::a774]) by lamorak.hansenpartnership.com (Postfix) with ESMTPSA id 838361C0993; Wed, 26 Feb 2025 09:45:54 -0500 (EST) Message-ID: <16127450a24e9df8112a347fe5f6df9c9cca2926.camel@HansenPartnership.com> Subject: Re: C aggregate passing (Rust kernel policy) From: James Bottomley To: Greg KH Cc: 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 Date: Wed, 26 Feb 2025 09:45:53 -0500 In-Reply-To: <2025022611-work-sandal-2759@gregkh> References: <5E3FEDC4-DBE3-45C7-A331-DAADD3E7EB42@zytor.com> <2rrp3fmznibxyg3ocvsfasfnpwfp2skhf4x7ihrnvm72lemykf@lwp2jkdbwqgm> <2025022611-work-sandal-2759@gregkh> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Wed, 2025-02-26 at 15:39 +0100, Greg KH wrote: > On Wed, Feb 26, 2025 at 09:26:50AM -0500, James Bottomley wrote: > > On Wed, 2025-02-26 at 14:53 +0100, Miguel Ojeda wrote: > > > On Wed, Feb 26, 2025 at 2:03 PM Ventura Jack > > > wrote: > > [...] > > > > Exception/unwind safety may be another subject that increases > > > > the difficulty of writing unsafe Rust. > > > > > > Note that Rust panics in the kernel do not unwind. > > > > I presume someone is working on this, right?  While rust isn't > > pervasive enough yet for this to cause a problem, dumping a > > backtrace is one of the key things we need to diagnose how > > something went wrong, particularly for user bug reports where they > > can't seem to bisect. > > The backtrace is there, just like any other call to BUG() provides, > which is what the rust framework calls for this. >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. Regards, James