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 3C08136C9C5; Thu, 25 Jun 2026 01:25:54 +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=1782350755; cv=none; b=t4t0VoaJ8fEMjWG/gCQ6p6XG04WUf7i+aGSXnFlMk3q8JL3GKv5OhoYuxL1D5mujPBFo7hnTDWvFv1kISa7Phi0s8q3TOkhM5L1qWlgWpxQL3il+4lfEDhJF5JhlMmma6pHqOpMFEhKd3cOmHSkri/fv1ye6X9GreV6WTuGJWv8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782350755; c=relaxed/simple; bh=SY5Euj1qjdj0hfbLzgT53pUkfLUwthg/2yyZlBKd2tM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=KKCdKHh9k4NLVaAn1SMrZO53YKcyr55Eq6glOZuTrpBdRHc3vDcZCnxI53g1gh4T6/8ncEuSyX5fc+TsLDgf2jSaCMhde3FT732jVyQ8MDN4tN/xzhPvuQbj3GMUKtWP/QAgFAglNUgfa+Yyig0HSq/afInrGuWhADPxE/7BT1Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C6hF8yNd; 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="C6hF8yNd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CDAE81F000E9; Thu, 25 Jun 2026 01:25:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782350753; bh=ErdX3RmX4qYmDR6Moys+BShnnPOkKKCoL22WcV9rF9g=; h=From:To:Cc:Subject:Date; b=C6hF8yNdc+O8N8OSv4/F4PEee1OV19zK0lJ0kJe5c6dVFubobUc81MpiEyDwk/nzW O22kbahqM/11GKdQ4fzPevoXz9s/wxRlNrKs5n583aM9zcuXpXB8e8MVS1aXvntK0w CoUdefYjIpZaqYl+VKHQObrSH9/afgmeXQwb4nd3yarNfcGcriQqmKEXBELQe0t510 kgo0KMAjMGw+373r/dCicEn3KgWQhUKg/X0CZLTksVpM7uCeffaso+aRKEenmPeN4d CEGVdfEGl3C6BxlfqP7kd5y07/2yo9flWXlJEsF5r0Ci6d4AQXN6pWprta/qt4fXi8 t5NtDTQKjyLtg== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Mathieu Desnoyers Cc: Jonathan Corbet , Shuah Khan , Masami Hiramatsu , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v9 0/9] tracing/probes: Add more typecast features Date: Thu, 25 Jun 2026 10:25:49 +0900 Message-ID: <178235074943.766912.25308838431649508.stgit@devnote2> X-Mailer: git-send-email 2.43.0 User-Agent: StGit/0.19 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="utf-8" Content-Transfer-Encoding: 8bit Hi, Here is the 9th version of series to introduce more typecast features to probe events. The previous version is here: https://lore.kernel.org/all/178231208703.732967.1160700962651040729.stgit@devnote2/ In this version, I removed picked bugfix patch, prohibit percpu access method on non-kernel probes [8/9], and add a test case to check the new syntax[9/9]. This series extends BTF typecast feature 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 6. Support event fields without $ prefix on eprobes. Now eprobe events can access its event fields. And added fetcharg dump feature (for debug) and updated test scripts to test part of them. Thanks, --- base-commit: c69b5f959286395e94c237ce6d7d4970bad7f6e3 Masami Hiramatsu (Google) (9): tracing/probes: Allow eprobe to use variable without $ prefix 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 | 12 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 | 579 ++++++++++++++++---- kernel/trace/trace_probe.h | 100 ++- kernel/trace/trace_probe_tmpl.h | 25 + 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 ++ .../test.d/dynevent/btf_typecast_accepted.tc | 107 ++++ .../test.d/dynevent/eprobes_syntax_errors.tc | 6 .../ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 12 .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 12 .../ftrace/test.d/kprobe/uprobe_syntax_errors.tc | 5 20 files changed, 876 insertions(+), 154 deletions(-) create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/btf_probe_event.tc create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/btf_typecast_accepted.tc -- Masami Hiramatsu (Google)