From patchwork Mon Mar 4 03:39:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13580004 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A5FC22F35; Mon, 4 Mar 2024 03:40:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709523601; cv=none; b=uuIC5ZAvpG5we8OqiAlWq9usZvlCD5Cdb7HZCLWziXmqB5G4hADjJaLOhCf9iNgyaV7FQVf3IZWla8+9gs0Xq8RVLnhEk5S1KjNugeHmu2sWVV/stw3s5CVzkZcVlq4UDKeZuyZVnCt1qZSSTq4Pm0BUbcRaQfxIy+gFhYfodAE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709523601; c=relaxed/simple; bh=PSql8T+SB1nHve+XLIxaaalYKdBXrVJvU38xsLLMMdQ=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=W5L1KsMUV5p8LEW4fBWykLdN1Ff6W3OzohBPXRXnPUpmXShMi1Wm/Cv9KHFMinpSeuAY9FUWMTC0NGiA5Qh3CaZCdVTvKynjOtF/0hoOYlgzEdYiVgTN5iIifnqI17Ra3qqLqwijEYP1SU3RY/UoUe+CeAPu/iIwFpVqo69dPmY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Oh9wgkeq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Oh9wgkeq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70044C433C7; Mon, 4 Mar 2024 03:39:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709523601; bh=PSql8T+SB1nHve+XLIxaaalYKdBXrVJvU38xsLLMMdQ=; h=From:To:Cc:Subject:Date:From; b=Oh9wgkeqk/wDfQFQkSH8NnelRNo+gVDZoebrTJzmoK+9xli/KBi2D3cLwLdVWl0Cy +61oWLw5X1s5FgAVT0Y9jtvPu6bEljxwDCEDBVEvxM2wpEhaZ/UgQkoDJ7gxZKAnrB DEMP2I8FwCX/iFAajaMFQHEshpbjXboPsGprOJj8sU+MITr9yqjStN+UjGP+KM/09a YYWZYzZ5LgMAuQlHUo10UAc/+lpr4OUu8S3HUm8RWwYmysDD5Zje/kSI67MsU1rYLu g9pORQ9xEeedtgTn6pMwremyJO2Ua0a2rsZTkhshhiOpIetZScpHpCe7REFcgFOdx/ MeRquWoyiuNQQ== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Jiri Olsa Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, mhiramat@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v3 0/8] tracing/probes: Support function parameter access from return probe Date: Mon, 4 Mar 2024 12:39:56 +0900 Message-Id: <170952359657.229804.14867636035660590574.stgit@devnote2> X-Mailer: git-send-email 2.34.1 User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hi, Here is version 3 series of patches to support accessing function entry data from function *return* probes (including kretprobe and fprobe-exit event). The previous version is here; https://lore.kernel.org/all/170891987362.609861.6767830614537418260.stgit@devnote2/ In this version, [1/8] is a bugfix patch (but note that this is already pushed to probes-fixes-v6.8-rc5, just for reference), updated [4/8] changelog and build error, fixes selftests error [6/8], update document[8/8] and added Steve's reviewed-by. This allows us to access the results of some functions, which returns the error code and its results are passed via function parameter, such as an structure-initialization function. For example, vfs_open() will link the file structure to the inode and update mode. Thus we can trace that changes. # echo 'f vfs_open mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events # echo 'f vfs_open%return mode=file->f_mode:x32 inode=file->f_inode:x64' >> dynamic_events # echo 1 > events/fprobes/enable # cat trace sh-131 [006] ...1. 1945.714346: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x2 inode=0x0 sh-131 [006] ...1. 1945.714358: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4d801e inode=0xffff888008470168 cat-143 [007] ...1. 1945.717949: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0 cat-143 [007] ...1. 1945.717956: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0x4a801d inode=0xffff888005f78d28 cat-143 [007] ...1. 1945.720616: vfs_open__entry: (vfs_open+0x4/0x40) mode=0x1 inode=0x0 cat-143 [007] ...1. 1945.728263: vfs_open__exit: (do_open+0x274/0x3d0 <- vfs_open) mode=0xa800d inode=0xffff888004ada8d8 So as you can see those fields are initialized at exit. This series is based on v6.8-rc5 kernel or you can checkout from https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git/log/?h=topic/entry-data Thank you, --- Masami Hiramatsu (Google) (8): fprobe: Fix to allocate entry_data_size buffer with rethook instances tracing/fprobe-event: cleanup: Fix a wrong comment in fprobe event tracing/probes: Cleanup probe argument parser tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init tracing: Remove redundant #else block for BTF args from README tracing/probes: Support $argN in return probe (kprobe and fprobe) selftests/ftrace: Add test cases for entry args at function exit Documentation: tracing: Add entry argument access at function exit Documentation/trace/fprobetrace.rst | 31 + Documentation/trace/kprobetrace.rst | 9 kernel/trace/fprobe.c | 14 - kernel/trace/trace.c | 5 kernel/trace/trace_eprobe.c | 8 kernel/trace/trace_fprobe.c | 59 ++- kernel/trace/trace_kprobe.c | 58 ++- kernel/trace/trace_probe.c | 417 ++++++++++++++------ kernel/trace/trace_probe.h | 30 + kernel/trace/trace_probe_tmpl.h | 10 kernel/trace/trace_uprobe.c | 14 - .../ftrace/test.d/dynevent/fprobe_entry_arg.tc | 18 + .../ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 4 .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 2 .../ftrace/test.d/kprobe/kretprobe_entry_arg.tc | 18 + 15 files changed, 521 insertions(+), 176 deletions(-) create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_entry_arg.tc create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_entry_arg.tc -- Masami Hiramatsu (Google)