[sysprof] kernel-symbol: delay symbol filtering until lookup

[Christian Hergert <chergert src gnome org>]

commit 3b3252e0504d3b46cb22b8f6875f3b29f8ae43fb
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jan 29 02:09:31 2018 -0800

    kernel-symbol: delay symbol filtering until lookup
    
    We don't want to avoid adding the symbols to the index table, or we will
    get the wrong addresses.
    
    So instead, add them, and then ignore the symbols upon lookup.

 lib/symbols/sp-kernel-symbol.c |   38 +++++++++++++++++++++-----------------
 1 files changed, 21 insertions(+), 17 deletions(-)
---
diff --git a/lib/symbols/sp-kernel-symbol.c b/lib/symbols/sp-kernel-symbol.c
index db8c147..8eb8087 100644
--- a/lib/symbols/sp-kernel-symbol.c
+++ b/lib/symbols/sp-kernel-symbol.c
@@ -28,6 +28,7 @@
 
 static GArray *kernel_symbols;
 static GStringChunk *kernel_symbol_strs;
+static GHashTable *kernel_symbols_skip_hash;
 static const gchar *kernel_symbols_skip[] = {
   /* IRQ stack */
   "common_interrupt",
@@ -77,15 +78,10 @@ sp_kernel_symbol_compare (gconstpointer a,
 }
 
 static inline gboolean
-is_ignored (GHashTable  *skip,
-            const gchar *name,
-            guint8       type)
+type_is_ignored (guint8 type)
 {
   /* Only allow symbols in the text (code) section */
-  if (type != 't' && type != 'T')
-    return TRUE;
-
-  return g_hash_table_contains (skip, name);
+  return (type != 't' && type != 'T');
 }
 
 static gboolean
@@ -122,7 +118,7 @@ failure:
 }
 
 static gboolean
-sp_kernel_symbol_load_from_sysprofd (GHashTable *skip)
+sp_kernel_symbol_load_from_sysprofd (void)
 {
   g_autoptr(GDBusConnection) conn = NULL;
   g_autoptr(GVariant) ret = NULL;
@@ -134,8 +130,6 @@ sp_kernel_symbol_load_from_sysprofd (GHashTable *skip)
   guint64 addr;
   guint8 type;
 
-  g_assert (skip != NULL);
-
   if (!(conn = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, NULL)))
     return FALSE;
 
@@ -171,7 +165,7 @@ sp_kernel_symbol_load_from_sysprofd (GHashTable *skip)
     {
       SpKernelSymbol sym;
 
-      if (is_ignored (skip, name, type))
+      if (type_is_ignored (type))
         continue;
 
       sym.address = addr;
@@ -206,6 +200,7 @@ sp_kernel_symbol_load (void)
   skip = g_hash_table_new (g_str_hash, g_str_equal);
   for (guint i = 0; i < G_N_ELEMENTS (kernel_symbols_skip); i++)
     g_hash_table_insert (skip, (gchar *)kernel_symbols_skip[i], NULL);
+  kernel_symbols_skip_hash = g_steal_pointer (&skip);
 
   kernel_symbol_strs = g_string_chunk_new (4096);
   ar = g_array_new (FALSE, TRUE, sizeof (SpKernelSymbol));
@@ -217,7 +212,7 @@ sp_kernel_symbol_load (void)
     {
       SpKernelSymbol sym;
 
-      if (is_ignored (skip, name, type))
+      if (type_is_ignored (type))
         continue;
 
       sym.address = addr;
@@ -235,7 +230,7 @@ sp_kernel_symbol_load (void)
   return TRUE;
 
 query_daemon:
-  if (sp_kernel_symbol_load_from_sysprofd (skip))
+  if (sp_kernel_symbol_load_from_sysprofd ())
     return TRUE;
 
   g_warning ("Kernel symbols will not be available.");
@@ -288,6 +283,7 @@ const SpKernelSymbol *
 sp_kernel_symbol_from_address (SpCaptureAddress address)
 {
   const SpKernelSymbol *first;
+  const SpKernelSymbol *ret;
 
   if G_UNLIKELY (kernel_symbols == NULL)
     {
@@ -311,8 +307,16 @@ sp_kernel_symbol_from_address (SpCaptureAddress address)
   if (address < first->address)
     return NULL;
 
-  return sp_kernel_symbol_lookup ((SpKernelSymbol *)(gpointer)kernel_symbols->data,
-                                  address,
-                                  0,
-                                  kernel_symbols->len - 1);
+  ret = sp_kernel_symbol_lookup ((SpKernelSymbol *)(gpointer)kernel_symbols->data,
+                                 address,
+                                 0,
+                                 kernel_symbols->len - 1);
+
+  /* We resolve all symbols, including ignored symbols so that we
+   * don't give back the wrong function juxtapose an ignored func.
+   */
+  if (ret != NULL && g_hash_table_contains (kernel_symbols_skip_hash, ret->name))
+    return NULL;
+
+  return ret;
 }