From d07f0b120642f442d81a61f68a9325fb7717004f Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Tue, 4 Jun 2013 17:44:26 +0200 Subject: perf stat: Avoid sending SIGTERM to random processes This patch fixes a problem with perf stat whereby on termination it may send a SIGTERM signal to random processes on systems with high PID recycling. I got some actual bug reports on this. There is race between the SIGCHLD and sig_atexit() handlers. This patch addresses this problem by clearing child_pid in the SIGCHLD handler. Signed-off-by: Stephane Eranian Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20130604154426.GA2928@quad Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) (limited to 'tools/perf/builtin-stat.c') diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 7e910bab1097..95768afaae3e 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -87,7 +87,7 @@ static int run_count = 1; static bool no_inherit = false; static bool scale = true; static enum aggr_mode aggr_mode = AGGR_GLOBAL; -static pid_t child_pid = -1; +static volatile pid_t child_pid = -1; static bool null_run = false; static int detailed_run = 0; static bool big_num = true; @@ -1148,13 +1148,34 @@ static void skip_signal(int signo) done = 1; signr = signo; + /* + * render child_pid harmless + * won't send SIGTERM to a random + * process in case of race condition + * and fast PID recycling + */ + child_pid = -1; } static void sig_atexit(void) { + sigset_t set, oset; + + /* + * avoid race condition with SIGCHLD handler + * in skip_signal() which is modifying child_pid + * goal is to avoid send SIGTERM to a random + * process + */ + sigemptyset(&set); + sigaddset(&set, SIGCHLD); + sigprocmask(SIG_BLOCK, &set, &oset); + if (child_pid != -1) kill(child_pid, SIGTERM); + sigprocmask(SIG_SETMASK, &oset, NULL); + if (signr == -1) return; -- cgit v1.2.3 From 582ec0829b3dd74d8c0f58403a3f9df8cbaa9c7d Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Fri, 5 Jul 2013 19:06:45 +0200 Subject: perf stat: Fix per-socket output bug for uncore events This patch fixes a problem reported by Andi Kleen on perf stat when measuring uncore events: # perf stat --per-socket -e uncore_pcu/event=0x0/ -I1000 -a sleep 2 It would not report counts for the second socket. That was due to a cpu mapping bug in print_aggr(). This patch also fixes the socket numbering bug for events. Reported-by: Andi Kleen Signed-off-by: Stephane Eranian Tested-by: Andi Kleen Cc: Andi Kleen Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: zheng.z.yan@intel.com Link: http://lkml.kernel.org/r/20130705170645.GA32519@quad Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'tools/perf/builtin-stat.c') diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 95768afaae3e..352fbd7ff4a1 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -924,7 +924,7 @@ static void abs_printout(int cpu, int nr, struct perf_evsel *evsel, double avg) static void print_aggr(char *prefix) { struct perf_evsel *counter; - int cpu, s, s2, id, nr; + int cpu, cpu2, s, s2, id, nr; u64 ena, run, val; if (!(aggr_map || aggr_get_id)) @@ -936,7 +936,8 @@ static void print_aggr(char *prefix) val = ena = run = 0; nr = 0; for (cpu = 0; cpu < perf_evsel__nr_cpus(counter); cpu++) { - s2 = aggr_get_id(evsel_list->cpus, cpu); + cpu2 = perf_evsel__cpus(counter)->map[cpu]; + s2 = aggr_get_id(evsel_list->cpus, cpu2); if (s2 != id) continue; val += counter->counts->cpu[cpu].val; @@ -948,7 +949,7 @@ static void print_aggr(char *prefix) fprintf(output, "%s", prefix); if (run == 0 || ena == 0) { - aggr_printout(counter, cpu, nr); + aggr_printout(counter, id, nr); fprintf(output, "%*s%s%*s", csv_output ? 0 : 18, -- cgit v1.2.3