Improve use of GCC sanitizers in CI runs (#811)

* Suppress leaks reported in system libraries during LSAN run

* Remove thread sanitizer (TSAN) from CI GCC analysis run

Previously TSAN provided no meaningful results when DOSBox was
launched inside CI with the "immediate exit" command, ie:

  dosbox -c exit

However, allowing it to initialize registered "programs"
and the mixer (and so on) does produce meaningful results,
which we accomplish using AUTOTYPE to type "exit" for us:

  dosbox -c "autotype e x i t enter"

However, within CI, we use the virtual X11 environment, which
unfortunately now conflicts with the TSAN harness, causing XVFB
itself to segfault (without any TSAN harness output):

  SEGV on unknown address 0x000000000000
  pc 0x000000000000 bp 0x7ffdf8bf4510 sp 0x7ffdf8bf44c8 T10341
  : 1

Threfore, because both ways of running TSAN aren't effective
within a GUI-less CI environment, this commit removes it for now.

TSAN works perfectly locally however, and the results are valid:
  ./build.sh -c gcc -t tsan
  <run like normal>

.github/scripts/build-and-run-sanitizers.sh

@@ -35,6 +35,9 @@ cd "$(dirname "${0}")/../.."
 # Make a directory to hold our build and run output
 mkdir -p "${logs}"
 
+# SAN-specific environment variables
+export LSAN_OPTIONS="suppressions=.lsan-suppress:verbosity=0"
+
 for sanitizer in "${sanitizers[@]}"; do
 
 	# Build DOSBox for each sanitizer
@@ -47,7 +50,7 @@ for sanitizer in "${sanitizers[@]}"; do
 	# Exercise the testcase(s) for each sanitizer
 	# Sanitizers return non-zero if one or more issues were found,
 	# so we or-to-true to ensure our script doesn't end here.
-	time xvfb-run ./src/dosbox -c exit \
+	time xvfb-run ./src/dosbox -c "autotype -w 0.1 e x i t enter" \
 		&> "${logs}/${compiler}-${sanitizer}-EnterExit.log" || true
 
 done

.github/workflows/analysis.yml

@@ -99,12 +99,11 @@ jobs:
           - name: Clang
             sanitizers: USAN
             usan:  0  # cleared out in our existing tests
-            tsan:  -1
             uasan: -1
           - name: GCC
-            sanitizers: TSAN UASAN
+            # TSAN excluded, harness segfaults inside virual-X11 environment
+            sanitizers: UASAN
             usan:  -1
-            tsan:  0  # our test does not trigger multiple threads yet
             uasan: 15
     steps:
       - uses: actions/checkout@v2
@@ -150,7 +149,6 @@ jobs:
       - name: Summarize issues
         env:
           USAN_LOG:  ${{ matrix.conf.name }}-logs/${{ matrix.conf.name }}-USAN-EnterExit.log.xz
-          TSAN_LOG:  ${{ matrix.conf.name }}-logs/${{ matrix.conf.name }}-TSAN-EnterExit.log.xz
           UASAN_LOG: ${{ matrix.conf.name }}-logs/${{ matrix.conf.name }}-UASAN-EnterExit.log.xz
         run: |
           # summary
@@ -165,12 +163,6 @@ jobs:
             xzcat "$USAN_LOG" | MAX_ISSUES=${{ matrix.conf.usan }} ./scripts/count-xsan-issues.py -
           fi
 
-          if [[ -f "$TSAN_LOG" ]] ; then
-            echo_bold "Thread sanitizer:"
-            echo
-            xzcat "$TSAN_LOG" | MAX_ISSUES=${{ matrix.conf.tsan }} ./scripts/count-xsan-issues.py -
-          fi
-
           if [[ -f "$UASAN_LOG" ]] ; then
             echo_bold "Undefined Behaviour + Address sanitizers:"
             echo

.lsan-suppress

@@ -0,0 +1,2 @@
+leak:/usr/lib/x86_64-linux-gnu/dri
+leak:/lib/x86_64-linux-gnu