From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Thu, 25 May 2023 23:15:20 +0000 (-0400)
Subject: Tests fix: test_callstack: output of addr2line incorrectly parsed
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=9613cdd03e4f00c3f9b98b13f7ac8ac3c45ceb56;p=lttng-tools.git

Tests fix: test_callstack: output of addr2line incorrectly parsed

Issue observed
--------------

The test_callstack test fails with GCC 13.1 with the following output:

  Traceback (most recent call last):
  File "/usr/lib/lttng-tools/ptest/tests/regression/././kernel//../../utils/parse-callstack.py", line 160, in <module>
  main()
  File "/usr/lib/lttng-tools/ptest/tests/regression/././kernel//../../utils/parse-callstack.py", line 155, in main
  raise Exception('Expected function name not found in recorded callstack')
  Exception: Expected function name not found in recorded callstack
  ok 10 - Destroy session callstack
  PASS: kernel/test_callstack 10 - Destroy session callstack
  not ok 11 - Validate userspace callstack
  FAIL: kernel/test_callstack 11 - Validate userspace callstack

Cause
-----

parse-callstack.py uses 'split()' to split the lines of addr2line's
output. By default, 'split()' splits a string on any whitespace.
Typically this was fine as addr2line's output doesn't contain spaces and
the function then splits on new lines.

Typical output of addr2line:

  $ addr2line -e ./tests/regression/kernel//../../utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack --functions --addresses 0x40124B
  0x000000000040124b
  my_gettid
  /tmp/test-callstack-master/src/lttng-tools/tests/utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack.c:40

However, with the test app compiled using gcc 13.1, a "discriminator"
annotation is present:

  0x0000000000401279
  fct_b
  /tmp/test-callstack-master/src/lttng-tools/tests/utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack.c:58 (discriminator 1)

Hence, by selecting the second to last element (-2, with negative
indexing), the addr2line function returns '(discriminator' as the
function name.

Solution
--------

The parsing code is changed to simply iterate on groups of 3 lines,
following addr2line's output format.

Fixes #1377

Change-Id: I8c1eab97e84ca7cad171904bed6660540061cf08
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/tests/utils/parse-callstack.py b/tests/utils/parse-callstack.py
index c3f0e2e9b..029100b61 100755
--- a/tests/utils/parse-callstack.py
+++ b/tests/utils/parse-callstack.py
@@ -26,14 +26,23 @@ def addr2line(executable, addr):
 
     status = subprocess.run(cmd, stdout=subprocess.PIPE, check=True)
 
-    addr2line_output = status.stdout.decode("utf-8")
-
-    # Omit the last 2 lines as the caller of main can not be determine
-    fcts = [addr2line_output.split()[-2]]
-
-    fcts = [ f for f in fcts if '??' not in f]
-
-    return fcts
+    addr2line_output = status.stdout.decode("utf-8").splitlines()
+    # addr2line's output is made of 3-tuples:
+    #   - address
+    #   - function name
+    #   - source location
+    if len(addr2line_output) % 3 != 0:
+        raise Exception('Unexpected addr2line output:\n\t{}'.format('\n\t'.join(addr2line_output)))
+
+    function_names = []
+    for address_line_number in range(0, len(addr2line_output), 3):
+        function_name = addr2line_output[address_line_number + 1]
+
+        # Filter-out unresolved functions
+        if "??" not in function_name:
+            function_names.append(addr2line_output[address_line_number + 1])
+
+    return function_names
 
 def extract_user_func_names(executable, raw_callstack):
     """