Ignore kallsyms mappings with address 0

kallsyms files with all addresses being 0 can happen. In this case,
ignore the mapping, as otherwise an address would resolve to a random
kernel symbol.
In addition, now perfparser shows a correct error message about being
unable to open the mapping.

Fixes KDAB/hotspot#117

Change-Id: Ib7ccf2f405f3a0a2149fa747175fb9feb11dfb07
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>

2 files changed, 26 insertions, 20 deletions

diff --git a/app/perfkallsyms.cpp b/app/perfkallsyms.cpp
index 1a64cbd..0ef016e 100644
--- a/app/perfkallsyms.cpp
+++ b/app/perfkallsyms.cpp
@@ -62,7 +62,8 @@ bool PerfKallsyms::parseMapping(const QString &path)
         if (eol == '\t')
             stream >> entry.module;
 
-        m_entries.push_back(entry);
+        if (entry.address != 0)
+            m_entries.push_back(entry);
     }
 
     if (valid && m_entries.isEmpty()) {
diff --git a/tests/auto/kallsyms/tst_kallsyms.cpp b/tests/auto/kallsyms/tst_kallsyms.cpp
index ab89096..6d9e31c 100644
--- a/tests/auto/kallsyms/tst_kallsyms.cpp
+++ b/tests/auto/kallsyms/tst_kallsyms.cpp
@@ -35,6 +35,7 @@ private slots:
         QTest::addColumn<quint64>("expectedAddress");
         QTest::addColumn<QByteArray>("expectedSymbol");
         QTest::addColumn<QByteArray>("expectedModule");
+        QTest::addColumn<bool>("expectedFailsParse");
 
         {
             const QByteArray kallsyms =
@@ -49,35 +50,36 @@ private slots:
                 "ffffffffa0000de0 T serio_unregister_driver\t[serio]\n";
 
             QTest::newRow("__per_cpu_start:0") << kallsyms << 0x0ull
-                 << 0x0ull << QByteArrayLiteral("__per_cpu_start") << QByteArray();
+                 << 0x0ull << QByteArray() << QByteArray() << false;
             QTest::newRow("_stext:0") << kallsyms << 0xffffffff810002b8ull
-                << 0xffffffff810002b8ull << QByteArrayLiteral("_stext") << QByteArray();
+                << 0xffffffff810002b8ull << QByteArrayLiteral("_stext") << QByteArray() << false;
             QTest::newRow("_stext:2") << kallsyms << (0xffffffff810002b8ll + 0x2ull)
-                << 0xffffffff810002b8ull << QByteArrayLiteral("_stext") << QByteArray();
+                << 0xffffffff810002b8ull << QByteArrayLiteral("_stext") << QByteArray() << false;
             QTest::newRow("xen_hypercall_set_gdt:0") << kallsyms << 0xffffffff81001040ull
-                << 0xffffffff81001040ull << QByteArrayLiteral("xen_hypercall_set_gdt") << QByteArray();
+                << 0xffffffff81001040ull << QByteArrayLiteral("xen_hypercall_set_gdt") << QByteArray() << false;
             QTest::newRow("xen_hypercall_set_gdt:256") << kallsyms << (0xffffffff81001040ull + 0x100ull)
-                << 0xffffffff81001040ull << QByteArrayLiteral("xen_hypercall_set_gdt") << QByteArray();
+                << 0xffffffff81001040ull << QByteArrayLiteral("xen_hypercall_set_gdt") << QByteArray() << false;
             QTest::newRow("xen_hypercall_set_gdt:256") << kallsyms << (0xffffffff81001040ull + 0x100ull)
-                << 0xffffffff81001040ull << QByteArrayLiteral("xen_hypercall_set_gdt") << QByteArray();
+                << 0xffffffff81001040ull << QByteArrayLiteral("xen_hypercall_set_gdt") << QByteArray() << false;
             QTest::newRow("serio_interrupt:0") << kallsyms << 0xffffffffa0000e80ull
-                << 0xffffffffa0000e80ull << QByteArrayLiteral("serio_interrupt") << QByteArrayLiteral("[serio]");
-        }
+                << 0xffffffffa0000e80ull << QByteArrayLiteral("serio_interrupt") << QByteArrayLiteral("[serio]") << false;
         {
             const auto kallsyms = QByteArrayLiteral("0000000000000000 A irq_stack_union");
             QTest::newRow("zeros-only") << kallsyms << 0x0ull
-                << 0x0ull << QByteArrayLiteral("irq_stack_union") << QByteArray();
+                << 0x0ull << QByteArray() << QByteArray() << true;
             QTest::newRow("zeros-only2") << kallsyms << std::numeric_limits<quint64>::max()
                 << 0x0ull
-                << QByteArrayLiteral("irq_stack_union") << QByteArray();
+                << QByteArray() << QByteArray() << true;
         }
         {
             const auto kallsyms = QByteArrayLiteral("          (null) A irq_stack_union");
             QTest::newRow("null-only") << kallsyms << 0x0ull
-                << 0x0ull << QByteArrayLiteral("irq_stack_union") << QByteArray();
+                << 0x0ull << QByteArray() << QByteArray() << true;
             QTest::newRow("null-only2") << kallsyms << std::numeric_limits<quint64>::max()
                 << 0x0ull
-                << QByteArrayLiteral("irq_stack_union") << QByteArray();
+                << QByteArrayLiteral("irq_stack_union") << QByteArray() << true;
+
+        }
         }
     }
 
@@ -88,6 +90,7 @@ private slots:
         QFETCH(quint64, expectedAddress);
         QFETCH(QByteArray, expectedSymbol);
         QFETCH(QByteArray, expectedModule);
+        QFETCH(bool, expectedFailsParse);
 
         QTemporaryFile file;
         QVERIFY(file.open());
@@ -95,13 +98,15 @@ private slots:
         file.flush();
 
         PerfKallsyms kallsyms;
-        QVERIFY(kallsyms.parseMapping(file.fileName()));
-        QVERIFY(kallsyms.errorString().isEmpty());
-
-        const auto entry = kallsyms.findEntry(address);
-        QCOMPARE(entry.address, expectedAddress);
-        QCOMPARE(entry.symbol, expectedSymbol);
-        QCOMPARE(entry.module, expectedModule);
+        QCOMPARE(kallsyms.parseMapping(file.fileName()), !expectedFailsParse);
+        QVERIFY(kallsyms.errorString().isEmpty() == !expectedFailsParse);
+
+        if (!expectedFailsParse) {
+            const auto entry = kallsyms.findEntry(address);
+            QCOMPARE(entry.address, expectedAddress);
+            QCOMPARE(entry.symbol, expectedSymbol);
+            QCOMPARE(entry.module, expectedModule);
+        }
     }
 
     void testProc()