perf: Fix various display bugs with parent filtering (58c34390) · Commits · 戴 / test

Hists that have been filtered, because they don't have callchains matching the parent filter, won't be printed. As such, hist_entry__snprintf() returns 0 for them, but we don't control this value and we always print the buffer, which might be untouched and then only made of random stack garbage. Not only does it paint the screen with barf, it also prints the callchains for these hists, even though they have been filtered, since the hist has been filtered as well. We need to check the return value of hist_entry__snprintf() and ignore the hist if it is 0, which means it didn't get any callchain matching the parent filter. This fixes the barf and the undesired callchains. Reported-by:

Ingo Molnar <mingo@elte.hu> Signed-off-by:

Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org>

tools/perf/util/hist.c

+16 −5

Original line number	Diff line number	Diff line
		@@ -631,9 +631,14 @@ int hist_entry__fprintf(struct hist_entry self, struct hists pair_hists,
		u64 session_total)
		{
		char bf[512];
		hist_entry__snprintf(self, bf, sizeof(bf), pair_hists,
		int ret;

		ret = hist_entry__snprintf(self, bf, sizeof(bf), pair_hists,
		show_displacement, displacement,
		true, session_total);
		if (!ret)
		return 0;

		return fprintf(fp, "%s\n", bf);
		}

		@@ -762,6 +767,7 @@ size_t hists__fprintf(struct hists self, struct hists pair,
		print_entries:
		for (nd = rb_first(&self->entries); nd; nd = rb_next(nd)) {
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
		int cnt;

		if (show_displacement) {
		if (h->pair != NULL)
		@@ -771,8 +777,13 @@ print_entries:
		displacement = 0;
		++position;
		}
		ret += hist_entry__fprintf(h, pair, show_displacement,
		cnt = hist_entry__fprintf(h, pair, show_displacement,
		displacement, fp, self->stats.total_period);
		/* Ignore those that didn't match the parent filter */
		if (!cnt)
		continue;

		ret += cnt;

		if (symbol_conf.use_callchain)
		ret += hist_entry__fprintf_callchain(h, fp, self->stats.total_period);

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