From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 E32CF36E342; Thu, 30 Oct 2025 18:57:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761850650; cv=none; b=fMB3MsIPhH3Mwr0jrvrmMwgSlSJT5GXEKi86NsSeBuPOViPEjkE+XlMoIpEejPcHs51K9TR/9kG8p7u+N9PJFxrrWkasuZ+F4d77tWVeEWO4W1cUYYsGI3BYE4qgniCEbC7VZOtKTxhK+8fOqZksjkfgYH7wFele+cdLKabpEG8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761850650; c=relaxed/simple; bh=DPN3R+jNqmq2nzo8zU5Q6weJpi9cFGa1aTDCxjEzbXU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=s3y8HFOdY70NsP/bLS8EfcreR0KyDXP6c/FFXBo3ORM+2DOZWx5UXoCof+CDgwDbhyFC8satW//nlBPy3yt/hOaA1sSSxXk2wU+SAoDbRIHVzYA0HPivxvd252bmZ/UeZTxA61l4mP08ybBiM7sT7H1+pr+kMpLelVLIrpvgpPY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=kXeQN4T/; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="kXeQN4T/" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=DPN3R+jNqmq2nzo8zU5Q6weJpi9cFGa1aTDCxjEzbXU=; b=kXeQN4T/MrS523pclpe0pc40fz dlvTiBkT+cDZ4/4pZvYiPGw2buLmXbnU9aUnz4X00FnJ0PUazFkW72u52hkNrUUtJtw5T/yPdL53K 9nnuZ5EBCWNw9k8ihjszAOrhCtDypG6M7oyTOmG/3HWQg8RCTXQ6QtfGzHuE3HGOr40qHqd5TSRKK pGpjyckPRrc/rqYV1s5lb3Ap2b0HiRFRbx8G+F0uFyGf5NtrUa1xWMuAKtNZ3KIDMbQ37yjKZEWy6 c9rz3MSebsDi8UTeWc1HrravwEOd5fbCBIng9QXIwfcQQcUevuo+1Z+svU832I1QWAVezpj/Rp83q u7WQWKMA==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vEWyA-00000009n9Q-3mvE; Thu, 30 Oct 2025 18:01:55 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 5D93830029E; Thu, 30 Oct 2025 19:57:25 +0100 (CET) Date: Thu, 30 Oct 2025 19:57:25 +0100 From: Peter Zijlstra To: Andi Kleen Cc: Mark Brown , Fangrui Song , linux-toolchains@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Concerns about SFrame viability for userspace stack walking Message-ID: <20251030185725.GC2989771@noisy.programming.kicks-ass.net> References: <3xd4fqvwflefvsjjoagytoi3y3sf7lxqjremhe2zo5tounihe4@3ftafgryadsr> <20251030102626.GR3245006@noisy.programming.kicks-ass.net> <87zf982s52.fsf@linux.intel.com> Precedence: bulk X-Mailing-List: linux-toolchains@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: On Thu, Oct 30, 2025 at 11:31:38AM -0700, Andi Kleen wrote: > Not on x86 at least. All my x86 systems have it, except for a few old > skylakes. About half of my systems have CET, but I just checked, none of them seem to actually use userspace shadow stacks. AFAICT Debian hasn't build their packages with this stuff on. But yeah, thanks for reminding me, we should definitely build a shstk unwinder.