From patchwork Mon Oct 14 12:31:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Metin Kaya X-Patchwork-Id: 13834927 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 90ADC19340F for ; Mon, 14 Oct 2024 12:31:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728909110; cv=none; b=cLXGFaFmVozm89ugu/m9ayGqUIKX4Pk9X4Yv4vDMHglN7buZRjESvsqS3KIH03i0zRLco2/HTuWCh0DNKm9/rO7NjyNg8wwwE2wV8jiXQo7miqXsx8vMXMNkTSafPEd0ociKhHXkVt0C8xOAtqG1YYNXiEkM+ezvm3Bynw8wop4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728909110; c=relaxed/simple; bh=sacAeAuODOwBlaD9AF61394SmgCzkKDrVoA7kynMOqc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ORB9VrM3tgQMO+A2Ts120Hoc4SHjbxqCPruCTG1rlVq3BJd57Z9FxsBBY6IOE2Oea5gjoIsshYtWaK43KXVsYw++0zynCanuiAfATltD7Aank7IGE7yAnNdmlMwjFgCxWEm54mrcQJUZZ6JHax9OQMl38G8goUiTrNtzQoNlrR4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 48A431684; Mon, 14 Oct 2024 05:32:17 -0700 (PDT) Received: from e133381.cambridge.arm.com (e133381.arm.com [10.1.198.34]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1C2603F71E; Mon, 14 Oct 2024 05:31:46 -0700 (PDT) From: Metin Kaya To: linux-trace-devel@vger.kernel.org Cc: metin.kaya@arm.com Subject: [PATCH v2 2/4] trace-cmd reset: Add option to preserve specific dynamic events Date: Mon, 14 Oct 2024 13:31:34 +0100 Message-Id: <20241014123136.3890807-3-metin.kaya@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241014123136.3890807-1-metin.kaya@arm.com> References: <20241014123136.3890807-1-metin.kaya@arm.com> Precedence: bulk X-Mailing-List: linux-trace-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 One may want to preserve some of the dynamic events (e.g., kprobes) during a trace-cmd reset. Thus, provide -k command line option for trace-cmd reset to allow keeping specified events untouched during the reset operation. For example, it's possible to prevent kprobes & kretprobes from being destroyed in trace-cmd reset with this patch: # Add kprobe and kretprobe for sys_open(): $ echo 'p do_sys_open' > /sys/kernel/tracing/kprobe_events $ echo 1 > /sys/kernel/tracing/events/kprobes/p_do_sys_open_0/enable $ echo 'r do_sys_open' >> /sys/kernel/tracing/kprobe_events $ echo 1 > /sys/kernel/tracing/events/kprobes/r_do_sys_open_0/enable $ cat /sys/kernel/tracing/kprobe_events p:kprobes/p_do_sys_open_0 do_sys_open r128:kprobes/r_do_sys_open_0 do_sys_open # Issue reset, but keep kprobes and kretprobes ('-k all' would keep # all existing dynamic events): $ trace-cmd reset -k kprobe -k kretprobe $ cat /sys/kernel/tracing/kprobe_events p:kprobes/p_do_sys_open_0 do_sys_open r128:kprobes/r_do_sys_open_0 do_sys_open # Issue reset, but this time only keep kretprobes: $ trace-cmd reset -k kretprobe $ cat /sys/kernel/tracing/kprobe_events r128:kprobes/r_do_sys_open_0 do_sys_open # Don't preserve any dynamic event: $ trace-cmd reset $ cat /sys/kernel/tracing/kprobe_events $ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=219302 Signed-off-by: Metin Kaya --- tracecmd/trace-record.c | 59 ++++++++++++++++++++++++++++++++++++----- tracecmd/trace-usage.c | 6 ++++- 2 files changed, 58 insertions(+), 7 deletions(-) diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c index 8c0039d4..a008cdfd 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -5399,11 +5399,15 @@ static void clear_error_log(void) clear_instance_error_log(instance); } -static void clear_all_dynamic_events(void) +static void clear_all_dynamic_events(unsigned int excluded_types) { - /* Clear event probes first, as they may be attached to other dynamic event */ - tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_EPROBE, true); - tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_ALL, true); + /* + * Clear event probes first (if they are not excluded), as they may be + * attached to other dynamic event. + */ + if (!(excluded_types & TRACEFS_DYNEVENT_EPROBE)) + tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_EPROBE, true); + tracefs_dynevent_destroy_all(~excluded_types & TRACEFS_DYNEVENT_ALL, true); } static void clear_func_filters(void) @@ -6036,11 +6040,51 @@ void trace_restart(int argc, char **argv) exit(0); } +/** + * find_dynevent_type - Find string formatted dynamic event type + * in "enum tracefs_dynevent_type". + * + * @type: Dynamic event type in string format. + * + * Returns an unsigned int value for the event specified in @type. + */ +static unsigned int find_dynevent_type(const char *type) +{ + /* WARN: Should be kept in sync with "enum tracefs_dynevent_type". */ + if (!strcmp(type, "kprobe")) + return TRACEFS_DYNEVENT_KPROBE; + else if (!strcmp(type, "kretprobe")) + return TRACEFS_DYNEVENT_KRETPROBE; + else if (!strcmp(type, "uprobe")) + return TRACEFS_DYNEVENT_UPROBE; + else if (!strcmp(type, "uretprobe")) + return TRACEFS_DYNEVENT_URETPROBE; + else if (!strcmp(type, "eprobe")) + return TRACEFS_DYNEVENT_EPROBE; + else if (!strcmp(type, "synth")) + return TRACEFS_DYNEVENT_SYNTH; + else if (!strcmp(type, "all")) + /* + * Unfortunately TRACEFS_DYNEVENT_ALL does not work here. + * Because tracefs_dynevent_destroy_all() assumes 0 means all + * and destroys all dynamic events. + */ + return TRACEFS_DYNEVENT_KPROBE | + TRACEFS_DYNEVENT_KRETPROBE | + TRACEFS_DYNEVENT_UPROBE | + TRACEFS_DYNEVENT_URETPROBE | + TRACEFS_DYNEVENT_EPROBE | + TRACEFS_DYNEVENT_SYNTH; + else + die("Invalid event type '%s'!\n", type); +} + void trace_reset(int argc, char **argv) { int c; int topt = 0; struct buffer_instance *instance = &top_instance; + unsigned int excluded_types = 0; init_top_instance(); @@ -6048,7 +6092,7 @@ void trace_reset(int argc, char **argv) int last_specified_all = 0; struct buffer_instance *inst; /* iterator */ - while ((c = getopt(argc-1, argv+1, "hab:B:td")) >= 0) { + while ((c = getopt(argc-1, argv+1, "hab:B:tdk:")) >= 0) { switch (c) { case 'h': @@ -6102,6 +6146,9 @@ void trace_reset(int argc, char **argv) instance->flags &= ~BUFFER_FL_KEEP; } break; + case 'k': + excluded_types |= find_dynevent_type(optarg); + break; default: usage(argv); break; @@ -6112,7 +6159,7 @@ void trace_reset(int argc, char **argv) set_buffer_size(); clear_filters(); clear_triggers(); - clear_all_dynamic_events(); + clear_all_dynamic_events(excluded_types); clear_error_log(); /* set clock to "local" */ reset_clock(); diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c index 8bbf2e3e..7d61a371 100644 --- a/tracecmd/trace-usage.c +++ b/tracecmd/trace-usage.c @@ -193,7 +193,7 @@ static struct usage_help usage_help[] = { { "reset", "disable all kernel tracing and clear the trace buffers", - " %s reset [-b size][-B buf][-a][-d][-t]\n" + " %s reset [-b size][-B buf][-k event][-a][-d][-t]\n" " Disables the tracer (may reset trace file)\n" " Used in conjunction with start\n" " -b change the kernel buffer size (in kilobytes per CPU)\n" @@ -201,6 +201,10 @@ static struct usage_help usage_help[] = { " -B reset the given buffer instance (may specify multiple -B)\n" " -a reset all instances (except top one)\n" " -t reset the top level instance (useful with -B or -a)\n" + " -k keep dynamic event during reset (can be specified multiple times).\n" + " Valid values are:\n" + " 'kprobe', 'kretprobe', 'uprobe', 'uretprobe',\n" + " 'eprobe', 'synth' and 'all'.\n" }, { "clear",