When analyzing samples in kernel space, use kernel symbols

Without this we cannot properly report any kernel stack traces and get
interesting error messages because the symbols aren't found in
userspace.

Change-Id: I981dbdac27beefa57c74bc9e8f41d5438e75668c
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

1 files changed, 8 insertions, 10 deletions

diff --git a/app/perfunwind.cpp b/app/perfunwind.cpp
index 849b220..fab3e15 100644
--- a/app/perfunwind.cpp
+++ b/app/perfunwind.cpp
@@ -509,8 +509,7 @@ void PerfUnwind::analyze(const PerfRecordSample &sample)
         return;
 
     const bool isKernel = ipIsInKernelSpace(sample.ip());
-
-    PerfSymbolTable *userSymbols = symbolTable(sample.pid());
+    PerfSymbolTable *symbols = symbolTable(isKernel ? s_kernelPid : sample.pid());
 
     for (int unwindingAttempt = 0; unwindingAttempt < 2; ++unwindingAttempt) {
         m_currentUnwind.isInterworking = false;
@@ -518,31 +517,30 @@ void PerfUnwind::analyze(const PerfRecordSample &sample)
         m_currentUnwind.sample = &sample;
         m_currentUnwind.frames.clear();
 
-        userSymbols->updatePerfMap();
+        symbols->updatePerfMap();
 
-        Dwfl *userDwfl = userSymbols->attachDwfl(&m_currentUnwind);
+        Dwfl *dwfl = symbols->attachDwfl(&m_currentUnwind);
         if (sample.callchain().length() > 0)
             resolveCallchain();
 
         // only try to unwind when resolveCallchain did not dirty the cache
-        if (!userSymbols->cacheIsDirty()) {
-            if (userDwfl && sample.registerAbi() != 0 && sample.userStack().length() > 0)
-                unwindStack(userDwfl);
+        if (!symbols->cacheIsDirty()) {
+            if (dwfl && sample.registerAbi() != 0 && sample.userStack().length() > 0)
+                unwindStack(dwfl);
             else
                 break;
         }
 
         // when the cache is dirty, we clean it up and try again, otherwise we can
         // stop as unwinding should have succeeded
-        if (userSymbols->cacheIsDirty())
-            userSymbols->clearCache(); // fail, try again
+        if (symbols->cacheIsDirty())
+            symbols->clearCache(); // fail, try again
         else
             break; // success
     }
 
     // If nothing was found, at least look up the IP
     if (m_currentUnwind.frames.isEmpty()) {
-        PerfSymbolTable *symbols = isKernel ? symbolTable(s_kernelPid) : userSymbols;
         m_currentUnwind.frames.append(symbols->lookupFrame(sample.ip(), isKernel,
                                                            &m_currentUnwind.isInterworking));
     }