From b9a46bba88001504235459c8410f17e6a7e38008 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 7 Mar 2011 21:13:40 +0100 Subject: [PATCH] perf top: Fix events overflow in top command The snprintf function returns number of printed characters even if it cross the size parameter. So passing enough events via '-e' parameter will cause segmentation fault. It's reproduced by following command: perf top -e `perf list | grep Tracepoint | awk -F'[' '\ {gsub(/[[:space:]]+/,"",$1);array[FNR]=$1}END{outputs=array[1];\ for (i=2;i<=FNR;i++){ outputs=outputs "," array[i];};print outputs}'` Attached patch is adding SNPRINTF macro that provides the overflow check and returns actuall number of printed characters. Reported-by: Han Pingtian Cc: Han Pingtian Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra LKML-Reference: <1299528821-17521-2-git-send-email-jolsa@redhat.com> Signed-off-by: Jiri Olsa Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/top.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/tools/perf/util/top.c b/tools/perf/util/top.c index 70a9c13..4f869da 100644 --- a/tools/perf/util/top.c +++ b/tools/perf/util/top.c @@ -61,6 +61,12 @@ static void rb_insert_active_sym(struct rb_root *tree, struct sym_entry *se) rb_insert_color(&se->rb_node, tree); } +#define SNPRINTF(buf, size, fmt, args...) \ +({ \ + size_t r = snprintf(buf, size, fmt, ## args); \ + r > size ? size : r; \ +}) + size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size) { struct perf_evsel *counter; @@ -70,7 +76,7 @@ size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size) size_t ret = 0; if (!perf_guest) { - ret = snprintf(bf, size, + ret = SNPRINTF(bf, size, " PerfTop:%8.0f irqs/sec kernel:%4.1f%%" " exact: %4.1f%% [", samples_per_sec, 100.0 - (100.0 * ((samples_per_sec - ksamples_per_sec) / @@ -81,7 +87,7 @@ size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size) float guest_kernel_samples_per_sec = top->guest_kernel_samples / top->delay_secs; float guest_us_samples_per_sec = top->guest_us_samples / top->delay_secs; - ret = snprintf(bf, size, + ret = SNPRINTF(bf, size, " PerfTop:%8.0f irqs/sec kernel:%4.1f%% us:%4.1f%%" " guest kernel:%4.1f%% guest us:%4.1f%%" " exact: %4.1f%% [", samples_per_sec, @@ -101,38 +107,38 @@ size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size) if (top->evlist->nr_entries == 1 || !top->display_weighted) { struct perf_evsel *first; first = list_entry(top->evlist->entries.next, struct perf_evsel, node); - ret += snprintf(bf + ret, size - ret, "%" PRIu64 "%s ", + ret += SNPRINTF(bf + ret, size - ret, "%" PRIu64 "%s ", (uint64_t)first->attr.sample_period, top->freq ? "Hz" : ""); } if (!top->display_weighted) { - ret += snprintf(bf + ret, size - ret, "%s", + ret += SNPRINTF(bf + ret, size - ret, "%s", event_name(top->sym_evsel)); } else list_for_each_entry(counter, &top->evlist->entries, node) { - ret += snprintf(bf + ret, size - ret, "%s%s", + ret += SNPRINTF(bf + ret, size - ret, "%s%s", counter->idx ? "/" : "", event_name(counter)); } - ret += snprintf(bf + ret, size - ret, "], "); + ret += SNPRINTF(bf + ret, size - ret, "], "); if (top->target_pid != -1) - ret += snprintf(bf + ret, size - ret, " (target_pid: %d", + ret += SNPRINTF(bf + ret, size - ret, " (target_pid: %d", top->target_pid); else if (top->target_tid != -1) - ret += snprintf(bf + ret, size - ret, " (target_tid: %d", + ret += SNPRINTF(bf + ret, size - ret, " (target_tid: %d", top->target_tid); else - ret += snprintf(bf + ret, size - ret, " (all"); + ret += SNPRINTF(bf + ret, size - ret, " (all"); if (top->cpu_list) - ret += snprintf(bf + ret, size - ret, ", CPU%s: %s)", + ret += SNPRINTF(bf + ret, size - ret, ", CPU%s: %s)", top->evlist->cpus->nr > 1 ? "s" : "", top->cpu_list); else { if (top->target_tid != -1) - ret += snprintf(bf + ret, size - ret, ")"); + ret += SNPRINTF(bf + ret, size - ret, ")"); else - ret += snprintf(bf + ret, size - ret, ", %d CPU%s)", + ret += SNPRINTF(bf + ret, size - ret, ", %d CPU%s)", top->evlist->cpus->nr, top->evlist->cpus->nr > 1 ? "s" : ""); } -- 2.7.4