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 62ADB3DDDB0; Wed, 5 Aug 2026 19:39:25 +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=1785958771; cv=none; b=QFxTySSr05nbIjWvT+qvuMZtYj2l03kf6P4YVdrXpMSopx2/nOlRzOf8BFjphgO8NTektRvbUBoQVRf2c8EVze1VQrX+cYBDrq7G/oEAPhWiZoVb7RHIPhecdI0FFYBi2Ty/MGAJyJmpiNgpw4qvT+tFWnC6YV0s6fVwSG/tZvo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785958771; c=relaxed/simple; bh=2eaG2oDsnWnhl9x5rQWEfwWlcul1Cx8idPicLwgn6oE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NxODzmkdhyFlTvo+akYACUY775Pap2Y6SUKT6JUk95M29m/5OxjRU85e+V+Kuob/6DMw9Cg9RTU8Ye6wxLzRiMNYCsjXNkRwnoe6E/7oEi9WWck8NVJrO/G0AslOluRAMLmur49AK4ojSAMDfz9SKzE1Ybmb9XIPN+PWY8DR47s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=WSiHOo/y; 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=pass 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="WSiHOo/y" 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=gtpJCCycl4O3UvKfejrnDc8jvQURyjbtenNDflVLceQ=; b=WSiHOo/y/oG95Lu+SGvtik8NCL bsDTJOSA/K0lf2xYzAAFAtX34Jvt9FPmcmuYMuaHs0I70SyVFfQZqiJ38IRiunnPi4g62WfPPyOKq 3BLtMy3fFh2SBiugoRtUt880SrqT5LzBJaVmMAr+7+NI7ffCdnPlgHgdVIJ6CKjGqG3ZoAOVjeM4Q D96fG79EJDTjNqcxmfnW0ejtLCGCNN+0DXBO1xi7VVMXhUk7eobx0WuSGyiX7lXmk2QWRMuvKfzCE 6eK9uQceU+u2+MTP7/nZdt9DWQM3HDM6cMtqoTPHIJ62PFSO2MxEaxnFQAW7fa2m95rtvH1Lm0OHv y5cyVMbQ==; 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 4.99.2 #2 (Red Hat Linux)) id 1wrhSJ-0000000AxZz-1GDO; Wed, 05 Aug 2026 19:39:11 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id AB6183003DE; Wed, 05 Aug 2026 21:39:09 +0200 (CEST) Date: Wed, 5 Aug 2026 21:39:09 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: "Masami Hiramatsu (Google)" , Ingo Molnar , x86@kernel.org, Jinchao Wang , Mathieu Desnoyers , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH v11 04/11] tracing: wprobe: Add watchpoint probe event based on hardware breakpoint Message-ID: <20260805193909.GP776954@noisy.programming.kicks-ass.net> References: <178565870538.714490.11309825813968306287.stgit@devnote2> <178565875046.714490.17724442147958346980.stgit@devnote2> <20260803070356.GV49951@noisy.programming.kicks-ass.net> <20260805153404.793691b8@gandalf.local.home> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260805153404.793691b8@gandalf.local.home> On Wed, Aug 05, 2026 at 03:34:04PM -0400, Steven Rostedt wrote: > On Mon, 3 Aug 2026 09:03:56 +0200 > Peter Zijlstra wrote: > > > > The new syntax is; > > > > > > w[:[GROUP/]EVENT] [r|w|rw]@[ADDR|SYM][:SIZE] [FETCH_ARGs] > > > > > > User also can use $addr to fetch the accessed address and $value to fetch > > > the accessed memory value (shorthand for '+0($addr)'). No other variables > > > are supported. > > > > This seems limited to kernel addresses only? Should not also userspace > > addresses be supported? > > Hmm, how would that work? The address is global for all tasks, so if you > add a user space address, what task would that be for? The one writing the > probe? Schedule the watchpoint along with the task of course. Given there is breakpoint/perf integration this should be trivial.