perf probe: Fix libdw memory leak

[ Upstream commit 4585038b8e ]

Add missing dwarf_cfi_end to free memory associated with probe_finder
cfi_eh which is allocated and owned via a call to
dwarf_getcfi_elf. Confusingly cfi_dbg shouldn't be freed as its memory
is owned by the passed in debuginfo struct. Add comments to highlight
this.

This addresses leak sanitizer issues seen in:
tools/perf/tests/shell/test_uprobe_from_different_cu.sh

Fixes: 270bde1e76 ("perf probe: Search both .eh_frame and .debug_frame sections for probe location")
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20241016235622.52166-3-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

tools/perf/util/probe-finder.c

@@ -1499,6 +1499,10 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
 	if (ret >= 0 && tf.pf.skip_empty_arg)
 		ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
 
+#if _ELFUTILS_PREREQ(0, 142)
+	dwarf_cfi_end(tf.pf.cfi_eh);
+#endif
+
 	if (ret < 0 || tf.ntevs == 0) {
 		for (i = 0; i < tf.ntevs; i++)
 			clear_probe_trace_event(&tf.tevs[i]);

tools/perf/util/probe-finder.h

@@ -81,9 +81,9 @@ struct probe_finder {
 
 	/* For variable searching */
 #if _ELFUTILS_PREREQ(0, 142)
-	/* Call Frame Information from .eh_frame */
+	/* Call Frame Information from .eh_frame. Owned by this struct. */
 	Dwarf_CFI		*cfi_eh;
-	/* Call Frame Information from .debug_frame */
+	/* Call Frame Information from .debug_frame. Not owned. */
 	Dwarf_CFI		*cfi_dbg;
 #endif
 	Dwarf_Op		*fb_ops;	/* Frame base attribute */