From 5e45187cc94814d2a5324bc18af994efc4fb4f7c Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 13 Aug 2014 16:12:48 +0000 Subject: [PATCH] perf probe: Fix --list option to show events only with uprobe events Current perf probe --list doesn't work if only CONFIG_UPROBE_EVENTS=y because it aborts when it fails to open kprobe_events file before checking uprobe_events file. This fixes --list option to show dynamic events if it can open either kprobe_events or uprobe_events. Only if it failed to open both of them, it shows an error message and aborts. Without this patch, if we run perf probe -l on the kernel configured with CONFIG_KPROBE_EVENTS=n and CONFIG_UPROBE_EVENTS=y, # perf probe -l /sys/kernel/debug/tracing/kprobe_events file does not exist - please rebuild ker Error: Failed to show event list. With this patch, # perf probe -l probe_perf:alloc_event (on alloc_event@lib/traceevent/event-parse.c in /home/fedora/ksrc/linux-3/tools/perf/perf) Changes in v2: - Use strerror_r instead of strerror. Reported-by: Naohiro Aota Signed-off-by: Masami Hiramatsu Cc: Ingo Molnar Cc: Naohiro Aota Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20140813161248.26440.84370.stgit@kbuild-fedora.novalocal Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-event.c | 89 +++++++++++++++++++++++------------ 1 file changed, 59 insertions(+), 30 deletions(-) diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 9a0a1839a377..50aa7f05ceb1 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -1780,10 +1780,11 @@ static void clear_probe_trace_event(struct probe_trace_event *tev) memset(tev, 0, sizeof(*tev)); } -static void print_warn_msg(const char *file, bool is_kprobe) +static void print_open_warning(int err, bool is_kprobe) { + char sbuf[128]; - if (errno == ENOENT) { + if (err == -ENOENT) { const char *config; if (!is_kprobe) @@ -1791,25 +1792,26 @@ static void print_warn_msg(const char *file, bool is_kprobe) else config = "CONFIG_KPROBE_EVENTS"; - pr_warning("%s file does not exist - please rebuild kernel" - " with %s.\n", file, config); - } else - pr_warning("Failed to open %s file: %s\n", file, - strerror(errno)); + pr_warning("%cprobe_events file does not exist" + " - please rebuild kernel with %s.\n", + is_kprobe ? 'k' : 'u', config); + } else if (err == -ENOTSUP) + pr_warning("Debugfs is not mounted.\n"); + else + pr_warning("Failed to open %cprobe_events: %s\n", + is_kprobe ? 'k' : 'u', + strerror_r(-err, sbuf, sizeof(sbuf))); } -static int open_probe_events(const char *trace_file, bool readwrite, - bool is_kprobe) +static int open_probe_events(const char *trace_file, bool readwrite) { char buf[PATH_MAX]; const char *__debugfs; int ret; __debugfs = debugfs_find_mountpoint(); - if (__debugfs == NULL) { - pr_warning("Debugfs is not mounted.\n"); - return -ENOENT; - } + if (__debugfs == NULL) + return -ENOTSUP; ret = e_snprintf(buf, PATH_MAX, "%s/%s", __debugfs, trace_file); if (ret >= 0) { @@ -1820,19 +1822,19 @@ static int open_probe_events(const char *trace_file, bool readwrite, ret = open(buf, O_RDONLY, 0); if (ret < 0) - print_warn_msg(buf, is_kprobe); + ret = -errno; } return ret; } static int open_kprobe_events(bool readwrite) { - return open_probe_events("tracing/kprobe_events", readwrite, true); + return open_probe_events("tracing/kprobe_events", readwrite); } static int open_uprobe_events(bool readwrite) { - return open_probe_events("tracing/uprobe_events", readwrite, false); + return open_probe_events("tracing/uprobe_events", readwrite); } /* Get raw string list of current kprobe_events or uprobe_events */ @@ -1940,27 +1942,47 @@ static int __show_perf_probe_events(int fd, bool is_kprobe) /* List up current perf-probe events */ int show_perf_probe_events(void) { - int fd, ret; + int kp_fd, up_fd, ret; setup_pager(); - fd = open_kprobe_events(false); - - if (fd < 0) - return fd; ret = init_symbol_maps(false); if (ret < 0) return ret; - ret = __show_perf_probe_events(fd, true); - close(fd); + kp_fd = open_kprobe_events(false); + if (kp_fd >= 0) { + ret = __show_perf_probe_events(kp_fd, true); + close(kp_fd); + if (ret < 0) + goto out; + } - fd = open_uprobe_events(false); - if (fd >= 0) { - ret = __show_perf_probe_events(fd, false); - close(fd); + up_fd = open_uprobe_events(false); + if (kp_fd < 0 && up_fd < 0) { + /* Both kprobes and uprobes are disabled, warn it. */ + if (kp_fd == -ENOTSUP && up_fd == -ENOTSUP) + pr_warning("Debugfs is not mounted.\n"); + else if (kp_fd == -ENOENT && up_fd == -ENOENT) + pr_warning("Please rebuild kernel with " + "CONFIG_KPROBE_EVENTS or/and " + "CONFIG_UPROBE_EVENTS.\n"); + else { + char sbuf[128]; + pr_warning("Failed to open kprobe events: %s.\n", + strerror_r(-kp_fd, sbuf, sizeof(sbuf))); + pr_warning("Failed to open uprobe events: %s.\n", + strerror_r(-up_fd, sbuf, sizeof(sbuf))); + } + ret = kp_fd; + goto out; } + if (up_fd >= 0) { + ret = __show_perf_probe_events(up_fd, false); + close(up_fd); + } +out: exit_symbol_maps(); return ret; } @@ -2075,8 +2097,11 @@ static int __add_probe_trace_events(struct perf_probe_event *pev, else fd = open_kprobe_events(true); - if (fd < 0) + if (fd < 0) { + print_open_warning(fd, !pev->uprobes); return fd; + } + /* Get current event names */ namelist = get_probe_trace_event_names(fd, false); if (!namelist) { @@ -2449,13 +2474,17 @@ int del_perf_probe_events(struct strlist *dellist) /* Get current event names */ kfd = open_kprobe_events(true); - if (kfd < 0) + if (kfd < 0) { + print_open_warning(kfd, true); return kfd; + } namelist = get_probe_trace_event_names(kfd, true); ufd = open_uprobe_events(true); - if (ufd >= 0) + if (ufd < 0) + print_open_warning(ufd, false); + else unamelist = get_probe_trace_event_names(ufd, true); if (namelist == NULL && unamelist == NULL) -- 2.30.2