From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 9A0ED37EFE4; Tue, 23 Jun 2026 13:54:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782222897; cv=none; b=Mm7q3m7x60aN1ekkAB9IeNspqtQLmUMMLgwos9dYrxEQ/c6cUTbQfzbTHbVxa4cSGmkHa9tB1jC6wlTBczAQqySH6erbUBtpwWuyk8S06NMR/weYAU3XI1MTMq2xswtaBx/DDJvtqVjzW14OnevuiCPVzB6fb/IOQyHA7k3lQYM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782222897; c=relaxed/simple; bh=/68utzRqhR106IezMe6HL563F8EtUs0AW9xqTvzK6pU=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=JPFVm7CMpiJY6mu/BQcJLA0DLD+0NGaNoad62hFiAT5EAd2up+yL6o3SSSqSkwnqrkrnDIQ0vnZQ1MCNagtBskNlw0de0LhYQiaB4J6K8L35F5i5rIxu3srJxDmVVLmixHm/yRZ+bHwUypaCXfYFliIB7UsJEaJzAtvv62rhDAI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vcll6fbK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vcll6fbK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 027501F000E9; Tue, 23 Jun 2026 13:54:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782222896; bh=aSCji0pWv4eufX4fgSb7qGv1Ss7fXCfVYg+H9V0MoFA=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=Vcll6fbKB7wYNJOLSQqyu5EOox1GdzMr/y4GV8TovfKTlZtHKgVEurVRVauJ3FR4p RFL+ivmEZQOlurnxl45pYlV/K6xwHdxv5txErxm2yWZ8zKljPrdYuqMyLFwleu+e9N T/LgLPg0qxeJl/lF1CDUCS0eYZ0zdJ3wsupon5GmyZksyJPFFAIUefZQBT+BSN5Vrt TCuwNjRzG0cH5ea3duUJtcUg0fZ/sqMRQtv+/wym2kj6vMokfcs9U3UKRPGAHX9vh4 4BMl0xW0sgpGvO2uD6BSC1uQosw2NhP/ooHfB91wvbdsNup3RM8ykoK7n+VOPDhS7F ptz6K4rCygWWw== Date: Tue, 23 Jun 2026 22:54:52 +0900 From: Masami Hiramatsu (Google) To: "Masami Hiramatsu (Google)" Cc: Steven Rostedt , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v7 00/10] tracing/probes: Add more typecast features Message-Id: <20260623225452.d0c8bba7a7a21126a08ed8b7@kernel.org> In-Reply-To: <178217904992.643090.15726197350652241270.stgit@devnote2> References: <178217904992.643090.15726197350652241270.stgit@devnote2> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 23 Jun 2026 10:44:10 +0900 "Masami Hiramatsu (Google)" wrote: > Hi, > > Here is the 7th version of series to introduce more typecast features > to probe events. The previous version is here: > > https://lore.kernel.org/all/178201238795.570818.15573963115625446598.stgit@devnote2/ > > In this version, I added 2 new fix and cleanup patches and update > according to Sashiko's review. [1/10] is a long-lived issue about > @+FOFFS, which was wrongly adding offset twice. [2/10] is a clean > up patch for renaming fetch_op name (good to dump it). > This is applicable against probes/core branch on linux-trace tree. I'll take the first 2 patches to probes/core, since those are obvious fix and cleanup. Thanks, > > Steve introduced BTF typecast feature for eprobe[1]. > This series extends it and add more options: > > 1. Expanding BTF typecast to kprobe and fprobe. > (currently only function entry/exit) > > 2. Introduce container_of like typecast. This adds a "assigned > member" option to the typecast. > > (STRUCT,MEMBER)VAR->ANOTHER_MEMBER > > This casts VAR to STRUCT type but the VAR is as the address > of STRUCT.MEMBER. In C, it is: > > container_of(VAR, STRUCT, MEMBER)->ANOTHER_MEMBER > > 3. Support nested typecast, e.g. > > (STRUCT)((STRUCT2)VAR->MEMBER2)->MEMBER > > the nest level must be smaller than 3. > > 4. Add $current variable to point "current" task_struct. > This is useful with typecast, e.g. > > (task_struct)$current->pid > > 5. per-cpu dereference support. > > Intrdouce this_cpu_read(VAR) and this_cpu_ptr(VAR) to > access per-cpu data on the current CPU (accessing other CPU > data is not stable, because it can be changed.) > > You can access the member of per-cpu data structure using > typecast like: > > (STRUCT)this_cpu_ptr(VAR)->MEMBER > > And added fetcharg dump feature (for debug) and updated test scripts > to test part of them. > > Thanks, > > --- > base-commit: 3ec75d0067f30eb5e0730f033766d6ab2feca7ae > > Masami Hiramatsu (Google) (10): > tracing/probes: Fix double addition of offset for @+FOFFSET > tracing/probes: Rename FETCH_OP_DATA to FETCH_OP_IMMSTR > tracing/probes: Support dumping fetcharg program for debugging dynamic events > tracing/probes: Support typecast for various probe events > tracing/probes: Support nested typecast > tracing/probes: Type casting always involves nested calls > tracing/probes: Support field specifier option for typecast > tracing/probes: Add $current variable support > tracing/probes: Add this_cpu_read() and this_cpu_ptr() dereference method to fetcharg > tracing/probes: Add a new testcase for BTF typecasts > > > Documentation/trace/eprobetrace.rst | 9 > Documentation/trace/fprobetrace.rst | 10 > Documentation/trace/kprobetrace.rst | 11 > kernel/trace/Kconfig | 11 > kernel/trace/trace.c | 8 > kernel/trace/trace_eprobe.c | 2 > kernel/trace/trace_fprobe.c | 2 > kernel/trace/trace_kprobe.c | 2 > kernel/trace/trace_probe.c | 582 ++++++++++++++++---- > kernel/trace/trace_probe.h | 98 ++- > kernel/trace/trace_probe_tmpl.h | 27 + > kernel/trace/trace_uprobe.c | 3 > samples/trace_events/trace-events-sample.c | 40 + > samples/trace_events/trace-events-sample.h | 34 + > .../ftrace/test.d/dynevent/btf_probe_event.tc | 51 ++ > .../ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 11 > .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 11 > .../ftrace/test.d/kprobe/uprobe_syntax_errors.tc | 5 > 18 files changed, 756 insertions(+), 161 deletions(-) > create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/btf_probe_event.tc > > -- > Masami Hiramatsu (Google) -- Masami Hiramatsu (Google)