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authorLike Xu <likexu@tencent.com>2021-09-27 16:11:15 +0800
committerArnaldo Carvalho de Melo <acme@redhat.com>2021-09-27 09:41:07 -0300
commit4da8b121884d84476f3d50d46a471471af1aa9df (patch)
tree9a4e7affa8f802f6d1a2c97b12a31eb77c928dc4 /tools
parente4fe5d7349e0b1c0d3da5b6b3e1efce591e85bd2 (diff)
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perf iostat: Fix Segmentation fault from NULL 'struct perf_counts_values *'
If the 'perf iostat' user specifies two or more iio_root_ports and also specifies the cpu(s) by -C which is not *connected to all* the above iio ports, the iostat_print_metric() will run into trouble: For example: $ perf iostat list S0-uncore_iio_0<0000:16> S1-uncore_iio_0<0000:97> # <--- CPU 1 is located in the socket S0 $ perf iostat 0000:16,0000:97 -C 1 -- ls port Inbound Read(MB) Inbound Write(MB) Outbound Read(MB) Outbound Write(MB) ../perf-iostat: line 12: 104418 Segmentation fault (core dumped) perf stat --iostat$DELIMITER$* The core-dump stack says, in the above corner case, the returned (struct perf_counts_values *) count will be NULL, and the caller iostat_print_metric() apparently doesn't not handle this case. 433 struct perf_counts_values *count = perf_counts(evsel->counts, die, 0); 434 435 if (count->run && count->ena) { (gdb) p count $1 = (struct perf_counts_values *) 0x0 The deeper reason is that there are actually no statistics from the user specified pair "iostat 0000:X, -C (disconnected) Y ", but let's fix it with minimum cost by adding a NULL check in the user space. Fixes: f9ed693e8bc0e7de ("perf stat: Enable iostat mode for x86 platforms") Signed-off-by: Like Xu <likexu@tencent.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20210927081115.39568-2-likexu@tencent.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/arch/x86/util/iostat.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/arch/x86/util/iostat.c b/tools/perf/arch/x86/util/iostat.c
index eeafe97b8105..792cd75ade33 100644
--- a/tools/perf/arch/x86/util/iostat.c
+++ b/tools/perf/arch/x86/util/iostat.c
@@ -432,7 +432,7 @@ void iostat_print_metric(struct perf_stat_config *config, struct evsel *evsel,
u8 die = ((struct iio_root_port *)evsel->priv)->die;
struct perf_counts_values *count = perf_counts(evsel->counts, die, 0);
- if (count->run && count->ena) {
+ if (count && count->run && count->ena) {
if (evsel->prev_raw_counts && !out->force_header) {
struct perf_counts_values *prev_count =
perf_counts(evsel->prev_raw_counts, die, 0);