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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 <phan@redhat.com>
Cc: Han Pingtian <phan@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1299528821-17521-2-git-send-email-jolsa@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2011-03-07 21:13:40 +01:00 committed by Arnaldo Carvalho de Melo
parent 2a8247a260
commit b9a46bba88
1 changed files with 18 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
tools/perf/util/top.c
View File

@ -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" : "");
}