Merge remote branch 'origin/master'

11 files changed, 269 insertions, 83 deletions

diff --git a/dwflpp.cxx b/dwflpp.cxx
index d3cecc44..4fb0d54e 100644
--- a/dwflpp.cxx
+++ b/dwflpp.cxx
@@ -1523,7 +1523,7 @@ dwflpp::emit_address (struct obstack *pool, Dwarf_Addr address)
           // This gives us the module name, and section name within the
           // module, for a kernel module (or other ET_REL module object).
           obstack_printf (pool, "({ unsigned long addr = 0; ");
-          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 "); ",
+          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 ", NULL); ",
                           modname, secname, reloc_address);
           obstack_printf (pool, "addr; })");
         }
@@ -1537,7 +1537,7 @@ dwflpp::emit_address (struct obstack *pool, Dwarf_Addr address)
           // kernel will never move after being loaded (unlike modules and
           // user-space dynamic share libraries).
           obstack_printf (pool, "({ static unsigned long addr = 0; ");
-          obstack_printf (pool, "if (addr==0) addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 "); ",
+          obstack_printf (pool, "if (addr==0) addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 ", NULL); ",
                           modname, secname, address); // PR10000 NB: not reloc_address
           obstack_printf (pool, "addr; })");
         }
@@ -1545,7 +1545,7 @@ dwflpp::emit_address (struct obstack *pool, Dwarf_Addr address)
         {
           enable_task_finder (sess);
           obstack_printf (pool, "({ unsigned long addr = 0; ");
-          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 "); ",
+          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 ", current); ",
                           modname, ".dynamic", reloc_address);
           obstack_printf (pool, "addr; })");
         }
diff --git a/runtime/sym.c b/runtime/sym.c
index cd0c8a71..06691dc9 100644
--- a/runtime/sym.c
+++ b/runtime/sym.c
@@ -19,6 +19,22 @@
 /* Callback that needs to be registered (in
    session.unwindsyms_modules) for every user task path for which we
    might need symbols or unwind info. */
+static int _stp_tf_exec_cb(struct stap_task_finder_target *tgt,
+			   struct task_struct *tsk,
+			   int register_p,
+			   int process_p)
+{
+#ifdef DEBUG_TASK_FINDER_VMA
+  _stp_dbug(__FUNCTION__, __LINE__,
+	    "tsk %d:%d , register_p: %d, process_p: %d\n",
+	    tsk->pid, tsk->tgid, register_p, process_p);
+#endif
+  if (process_p && ! register_p)
+    stap_drop_vma_maps(tsk);
+
+  return 0;
+}
+
 static int _stp_tf_mmap_cb(struct stap_task_finder_target *tgt,
 			   struct task_struct *tsk,
 			   char *path,
@@ -42,40 +58,22 @@ static int _stp_tf_mmap_cb(struct stap_task_finder_target *tgt,
 			if (strcmp(path, _stp_modules[i]->path) == 0)
 			{
 #ifdef DEBUG_TASK_FINDER_VMA
-				_stp_dbug(__FUNCTION__, __LINE__,
-					  "vm_cb: matched path %s to module\n",
-					  path);
+			  _stp_dbug(__FUNCTION__, __LINE__,
+				    "vm_cb: matched path %s to module (for sec: %s)\n",
+				    path, _stp_modules[i]->sections[0].name);
 #endif
-				module = _stp_modules[i];
-				// cheat...
-				// We are abusing the "first" section address
-				// here to indicate where the module (actually
-				// first segment) is loaded (which is why we
-				// are ignoring the offset). It would be good
-				// to redesign the stp_module/stp_section
-				// data structures to better align with the
-				// actual memory mappings we are interested
-				// in (especially the "section" naming is
-				// slightly confusing since what we really
-				// seem to mean are elf segments (which can
-				// contain multiple elf sections). PR11015.
-				if (strcmp(".dynamic",
-					   module->sections[0].name) == 0)
-				  {
-				    if (module->sections[0].addr == 0)
-				      module->sections[0].addr = addr;
-				    else if (module->sections[0].addr != addr)
-				      _stp_error ("Reloaded module '%s'"
-						  " at 0x%lx, was 0x%lx\n",
-						  path, addr,
-						  module->sections[0].addr);
-				  }
-				break;
+			  module = _stp_modules[i];
+			  /* XXX We really only need to register .dynamic
+			     sections, but .absolute exes are also necessary
+			     atm. */
+			  return stap_add_vma_map_info(tsk->group_leader,
+						       addr,
+						       addr + length,
+						       offset,
+						       module);
 			}
 		}
 	}
-	stap_add_vma_map_info(tsk->group_leader, addr, addr + length, offset,
-			      module);
 	return 0;
 }
 
@@ -84,15 +82,25 @@ static int _stp_tf_munmap_cb(struct stap_task_finder_target *tgt,
 			     unsigned long addr,
 			     unsigned long length)
 {
+        /* Unconditionally remove vm map info, ignore if not present. */
 	stap_remove_vma_map_info(tsk->group_leader, addr, addr + length, 0);
 	return 0;
 }
 
-/* XXX: this needs to be address-space-specific. */
-static unsigned long _stp_module_relocate(const char *module, const char *section, unsigned long offset)
+/* Returns absolute address of offset into module/section for given task.
+   If tsk == NULL module/section is assumed to be absolute/static already
+   (e.g. kernel, kernel-modules and static executables). Returns zero when
+   module and section couldn't be found (aren't in memory yet). */
+static unsigned long _stp_module_relocate(const char *module,
+					  const char *section,
+					  unsigned long offset,
+					  struct task_struct *tsk)
 {
+        /* XXX This doesn't look thread safe XXX */
 	static struct _stp_module *last = NULL;
 	static struct _stp_section *last_sec;
+        static struct task_struct *last_tsk;
+        static unsigned long last_offset;
 	unsigned i, j;
 
 	/* if module is -1, we invalidate last. _stp_del_module calls this when modules are deleted. */
@@ -110,8 +118,10 @@ static unsigned long _stp_module_relocate(const char *module, const char *sectio
 
 	/* Most likely our relocation is in the same section of the same module as the last. */
 	if (last) {
-		if (!strcmp(module, last->name) && !strcmp(section, last_sec->name)) {
-			offset += last_sec->addr;
+		if (!strcmp(module, last->name)
+                    && !strcmp(section, last_sec->name)
+                    && tsk == last_tsk) {
+			offset += last_offset;
 			dbug_sym(1, "cached address=%lx\n", offset);
 			return offset;
 		}
@@ -124,11 +134,33 @@ static unsigned long _stp_module_relocate(const char *module, const char *sectio
           for (j = 0; j < last->num_sections; j++) {
             last_sec = &last->sections[j];
             if (!strcmp(section, last_sec->name)) {
-            
-              if (last_sec->addr == 0) /* module/section not in memory */
-                continue;
-
-              offset += last_sec->addr;
+              /* mod and sec name match. tsk should match dynamic/static. */
+              if (last_sec->static_addr != 0) {
+                last_offset = last_sec->static_addr;
+	      } else {
+                if (!tsk) { /* static section, not in memory yet? */
+		  if (strcmp(".dynamic", section) == 0)
+		    _stp_error("internal error, _stp_module_relocate '%s' "
+			       "section '%s', should not be tsk dynamic\n",
+			       module, section);
+		  last = NULL;
+		  return 0;
+		} else { /* dynamic section, look up through tsk vma. */
+		  if (strcmp(".dynamic", last_sec->name) != 0) {
+		    _stp_error("internal error, _stp_module_relocate '%s' "
+			       "section '%s', should not be tsk dynamic\n",
+			       module, section);
+		    return 0;
+		  }
+		  if (stap_find_vma_map_info_user(tsk->group_leader, last,
+						  &last_offset, NULL,
+						  NULL) != 0) {
+		    last = NULL;
+		    return 0;
+		  }
+		}
+	      }
+              offset += last_offset;
               dbug_sym(1, "address=%lx\n", offset);
               return offset;
             }
@@ -140,11 +172,12 @@ static unsigned long _stp_module_relocate(const char *module, const char *sectio
 }
 
 /* Return module owner and, if sec != NULL, fills in closest section
-   of the address if found, return NULL otherwise.
-   XXX: needs to be address-space-specific. */
+   of the address if found, return NULL otherwise. Fills in rel_addr
+   (addr relative to closest section) when given. */
 static struct _stp_module *_stp_mod_sec_lookup(unsigned long addr,
 					       struct task_struct *task,
-					       struct _stp_section **sec)
+					       struct _stp_section **sec,
+					       unsigned long *rel_addr)
 {
   void *user = NULL;
   unsigned midx = 0;
@@ -160,11 +193,21 @@ static struct _stp_module *_stp_mod_sec_lookup(unsigned long addr,
 	  {
 	    struct _stp_module *m = (struct _stp_module *)user;
 	    if (sec)
-	      *sec = &m->sections[0]; // XXX check actual section and relocate
+	      *sec = &m->sections[0]; // dynamic user modules have one section.
+	    if (rel_addr)
+	      {
+		/* XXX .absolute sections really shouldn't be here... */
+		if (strcmp(".dynamic", m->sections[0].name) == 0)
+		  *rel_addr = addr - vm_start;
+		else
+		  *rel_addr = addr;
+	      }
 	    dbug_sym(1, "found section %s in module %s at 0x%lx\n",
 		     m->sections[0].name, m->name, vm_start);
 	    return m;
 	  }
+      /* XXX should really not fallthrough, but sometimes current is passed
+             when it shouldn't - see probefunc() for example. */
     }
 
   for (midx = 0; midx < _stp_num_modules; midx++)
@@ -174,12 +217,14 @@ static struct _stp_module *_stp_mod_sec_lookup(unsigned long addr,
 	{
 	  unsigned long sec_addr;
 	  unsigned long sec_size;
-	  sec_addr = _stp_modules[midx]->sections[secidx].addr;
+	  sec_addr = _stp_modules[midx]->sections[secidx].static_addr;
 	  sec_size = _stp_modules[midx]->sections[secidx].size;
 	  if (addr >= sec_addr && addr < sec_addr + sec_size)
             {
 	      if (sec)
 		*sec = & _stp_modules[midx]->sections[secidx];
+	      if (rel_addr)
+		*rel_addr = addr - sec_addr;
 	      return _stp_modules[midx];
 	    }
 	}
@@ -188,7 +233,6 @@ static struct _stp_module *_stp_mod_sec_lookup(unsigned long addr,
 }
 
 
-/* XXX: needs to be address-space-specific. */
 static const char *_stp_kallsyms_lookup(unsigned long addr, unsigned long *symbolsize,
                                         unsigned long *offset, 
                                         const char **modname, 
@@ -200,13 +244,14 @@ static const char *_stp_kallsyms_lookup(unsigned long addr, unsigned long *symbo
 	struct _stp_section *sec = NULL;
 	struct _stp_symbol *s = NULL;
 	unsigned end, begin = 0;
+	unsigned long rel_addr = 0;
 
-	m = _stp_mod_sec_lookup(addr, task, &sec);
+	m = _stp_mod_sec_lookup(addr, task, &sec, &rel_addr);
         if (unlikely (m == NULL || sec == NULL))
           return NULL;
         
         /* NB: relativize the address to the section. */
-        addr -= sec->addr;
+        addr = rel_addr;
 	end = sec->num_symbols;
 
 	/* binary search for symbols within the module */
@@ -268,9 +313,9 @@ static int _stp_module_check(void)
 		    /* notes end address */
 		    if (!strcmp(m->name, "kernel")) {
 			  notes_addr = _stp_module_relocate("kernel",
-					 "_stext", m->build_id_offset);
+					 "_stext", m->build_id_offset, NULL);
 			  base_addr = _stp_module_relocate("kernel",
-							   "_stext", 0);
+							   "_stext", 0, NULL);
                     } else {
 			  notes_addr = m->notes_sect + m->build_id_offset;
 			  base_addr = m->notes_sect;
@@ -446,14 +491,20 @@ static void _stp_sym_init(void)
         static struct stap_task_finder_target vmcb = {
                 // NB: no .pid, no .procname filters here.
                 // This means that we get a system-wide mmap monitoring
-                // widget while the script is running.  (The system-wideness may
-                // be restricted by stap -c or -x.)  But this seems to
-                // be necessary if we want to to stack tracebacks through arbitrary
-                // shared libraries.  XXX: There may be an optimization opportunity
-                // for executables (for which the main task-finder callback should be
-                // sufficient).
+                // widget while the script is running. (The
+                // system-wideness may be restricted by stap -c or
+                // -x.)  But this seems to be necessary if we want to
+                // to stack tracebacks through arbitrary shared libraries.
+                //
+                // XXX: There may be an optimization opportunity
+                // for executables (for which the main task-finder
+                // callback should be sufficient).
+                .pid = 0,
+                .procname = NULL,
+                .callback = &_stp_tf_exec_cb,
                 .mmap_callback = &_stp_tf_mmap_cb,
                 .munmap_callback = &_stp_tf_munmap_cb,
+                .mprotect_callback = NULL
         };
 	if (! initialized) {
                 int rc;
@@ -462,8 +513,10 @@ static void _stp_sym_init(void)
 #ifdef DEBUG_TASK_FINDER_VMA
                 _stp_dbug(__FUNCTION__, __LINE__, "registered vmcb");
 #endif
-                (void) rc; // XXX
-		initialized = 1;
+                if (rc != 0)
+                  _stp_error("Couldn't register task finder target: %d\n", rc);
+                else
+                  initialized = 1;
 	}
 #endif
 }
diff --git a/runtime/sym.h b/runtime/sym.h
index 9f2bdfd0..ce6ab736 100644
--- a/runtime/sym.h
+++ b/runtime/sym.h
@@ -17,7 +17,7 @@ struct _stp_symbol {
 
 struct _stp_section {
         const char *name;
-        unsigned long addr; /* XXX: belongs in per-address-space tables */
+        unsigned long static_addr; /* XXX non-null if everywhere the same. */
 	unsigned long size; /* length of the address space module covers. */
 	struct _stp_symbol *symbols;  /* ordered by address */
   	unsigned num_symbols;
@@ -70,7 +70,10 @@ static unsigned long _stp_kretprobe_trampoline;
    _stp_sym_init () should track vma maps. */
 static char _stp_need_vma_tracker;
 
-static unsigned long _stp_module_relocate (const char *module, const char *section, unsigned long offset);
+static unsigned long _stp_module_relocate (const char *module,
+					   const char *section,
+					   unsigned long offset,
+					   struct task_struct *tsk);
 static struct _stp_module *_stp_get_unwind_info (unsigned long addr);
 
 #endif /* _STP_SYM_H_ */
diff --git a/runtime/task_finder_vma.c b/runtime/task_finder_vma.c
index ed9c6f4f..9a32323f 100644
--- a/runtime/task_finder_vma.c
+++ b/runtime/task_finder_vma.c
@@ -270,6 +270,7 @@ stap_add_vma_map_info(struct task_struct *tsk, unsigned long vm_start,
 
 
 // Remove the vma entry from the vma hash table.
+// Returns -ESRCH if the entry isn't present.
 static int
 stap_remove_vma_map_info(struct task_struct *tsk, unsigned long vm_start,
 			     unsigned long vm_end, unsigned long vm_pgoff)
@@ -277,6 +278,7 @@ stap_remove_vma_map_info(struct task_struct *tsk, unsigned long vm_start,
 	struct hlist_head *head;
 	struct hlist_node *node;
 	struct __stp_tf_vma_entry *entry;
+	int rc = -ESRCH;
 
 	// Take a write lock since we are most likely going to delete
 	// after reading.
@@ -286,13 +288,15 @@ stap_remove_vma_map_info(struct task_struct *tsk, unsigned long vm_start,
 	if (entry != NULL) {
 		hlist_del(&entry->hlist);
 		__stp_tf_vma_put_free_entry(entry);
+                rc = 0;
 	}
 	write_unlock_irqrestore(&__stp_tf_vma_lock, flags);
-	return 0;
+	return rc;
 }
 
-// Finds vma info if the vma is present in the vma map hash table.
-// Returns ESRCH if not present.  The __stp_tf_vma_lock must *not* be
+// Finds vma info if the vma is present in the vma map hash table for
+// a given task and address (between vm_start and vm_end).
+// Returns -ESRCH if not present.  The __stp_tf_vma_lock must *not* be
 // locked before calling this function.
 static int
 stap_find_vma_map_info(struct task_struct *tsk, unsigned long vm_addr,
@@ -303,7 +307,7 @@ stap_find_vma_map_info(struct task_struct *tsk, unsigned long vm_addr,
 	struct hlist_node *node;
 	struct __stp_tf_vma_entry *entry;
 	struct __stp_tf_vma_entry *found_entry = NULL;
-	int rc = ESRCH;
+	int rc = -ESRCH;
 
 	unsigned long flags;
 	read_lock_irqsave(&__stp_tf_vma_lock, flags);
@@ -330,3 +334,62 @@ stap_find_vma_map_info(struct task_struct *tsk, unsigned long vm_addr,
 	read_unlock_irqrestore(&__stp_tf_vma_lock, flags);
 	return rc;
 }
+
+// Finds vma info if the vma is present in the vma map hash table for
+// a given task with the given user handle.
+// Returns -ESRCH if not present.  The __stp_tf_vma_lock must *not* be
+// locked before calling this function.
+static int
+stap_find_vma_map_info_user(struct task_struct *tsk, void *user,
+			    unsigned long *vm_start, unsigned long *vm_end,
+			    unsigned long *vm_pgoff)
+{
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct __stp_tf_vma_entry *entry;
+	struct __stp_tf_vma_entry *found_entry = NULL;
+	int rc = -ESRCH;
+
+	unsigned long flags;
+	read_lock_irqsave(&__stp_tf_vma_lock, flags);
+	head = &__stp_tf_vma_map[__stp_tf_vma_map_hash(tsk)];
+	hlist_for_each_entry(entry, node, head, hlist) {
+		if (tsk->pid == entry->pid
+		    && user == entry->user) {
+			found_entry = entry;
+			break;
+		}
+	}
+	if (found_entry != NULL) {
+		if (vm_start != NULL)
+			*vm_start = found_entry->vm_start;
+		if (vm_end != NULL)
+			*vm_end = found_entry->vm_end;
+		if (vm_pgoff != NULL)
+			*vm_pgoff = found_entry->vm_pgoff;
+		rc = 0;
+	}
+	read_unlock_irqrestore(&__stp_tf_vma_lock, flags);
+	return rc;
+}
+
+static int
+stap_drop_vma_maps(struct task_struct *tsk)
+{
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct hlist_node *n;
+	struct __stp_tf_vma_entry *entry;
+
+	unsigned long flags;
+	write_lock_irqsave(&__stp_tf_vma_lock, flags);
+	head = &__stp_tf_vma_map[__stp_tf_vma_map_hash(tsk)];
+        hlist_for_each_entry_safe(entry, node, n, head, hlist) {
+            if (tsk->pid == entry->pid) {
+		    hlist_del(&entry->hlist);
+		    __stp_tf_vma_put_free_entry(entry);
+            }
+        }
+	write_unlock_irqrestore(&__stp_tf_vma_lock, flags);
+	return 0;
+}
diff --git a/runtime/transport/symbols.c b/runtime/transport/symbols.c
index a214d1f2..e2f9fd65 100644
--- a/runtime/transport/symbols.c
+++ b/runtime/transport/symbols.c
@@ -61,7 +61,7 @@ static void _stp_do_relocation(const char __user *buf, size_t count)
             continue;
           else
             {
-              _stp_modules[mi]->sections[si].addr = msg.address;
+              _stp_modules[mi]->sections[si].static_addr = msg.address;
               break;
             }
         } /* loop over sections */
diff --git a/runtime/unwind.c b/runtime/unwind.c
index 7607770e..c8e3580d 100644
--- a/runtime/unwind.c
+++ b/runtime/unwind.c
@@ -496,7 +496,7 @@ static char *_stp_eh_enc_name(signed type)
 // and the elfutils base relocation done during loading of the .dwarf_frame
 // in translate.cxx.
 static unsigned long
-adjustStartLoc (unsigned long startLoc,
+adjustStartLoc (unsigned long startLoc, struct task_struct *tsk,
 		struct _stp_module *m,
 		struct _stp_section *s,
 		unsigned ptrType, int is_ehframe)
@@ -521,10 +521,14 @@ adjustStartLoc (unsigned long startLoc,
       return startLoc;
   }
 
-  if (strcmp (s->name, ".dynamic") == 0)
-    return startLoc + s->addr;
+  if (strcmp (s->name, ".dynamic") == 0) {
+    unsigned long vm_addr;
+    if (stap_find_vma_map_info_user(tsk->group_leader, m,
+				    &vm_addr, NULL, NULL) == 0)
+      return startLoc + vm_addr;
+  }
 
-  startLoc = _stp_module_relocate (m->name, s->name, startLoc);
+  startLoc = _stp_module_relocate (m->name, s->name, startLoc, tsk);
   startLoc -= m->dwarf_module_base;
   return startLoc;
 }
@@ -532,7 +536,7 @@ adjustStartLoc (unsigned long startLoc,
 /* If we previously created an unwind header, then use it now to binary search */
 /* for the FDE corresponding to pc. XXX FIXME not currently supported. */
 
-static u32 *_stp_search_unwind_hdr(unsigned long pc,
+static u32 *_stp_search_unwind_hdr(unsigned long pc, struct task_struct *tsk,
 				   struct _stp_module *m,
 				   struct _stp_section *s)
 {
@@ -581,7 +585,7 @@ static u32 *_stp_search_unwind_hdr(unsigned long pc,
 	do {
 		const u8 *cur = ptr + (num / 2) * (2 * tableSize);
 		startLoc = read_pointer(&cur, cur + tableSize, hdr[3]);
-		startLoc = adjustStartLoc(startLoc, m, s, hdr[3], 1);
+		startLoc = adjustStartLoc(startLoc, tsk, m, s, hdr[3], 1);
 		if (pc < startLoc)
 			num /= 2;
 		else {
@@ -590,7 +594,7 @@ static u32 *_stp_search_unwind_hdr(unsigned long pc,
 		}
 	} while (startLoc && num > 1);
 
-	if (num == 1 && (startLoc = adjustStartLoc(read_pointer(&ptr, ptr + tableSize, hdr[3]), m, s, hdr[3], 1)) != 0 && pc >= startLoc)
+	if (num == 1 && (startLoc = adjustStartLoc(read_pointer(&ptr, ptr + tableSize, hdr[3]), tsk, m, s, hdr[3], 1)) != 0 && pc >= startLoc)
 		fde = (void *)read_pointer(&ptr, ptr + tableSize, hdr[3]);
 
 	dbug_unwind(1, "returning fde=%lx startLoc=%lx", (unsigned long) fde, startLoc);
@@ -601,6 +605,7 @@ static u32 *_stp_search_unwind_hdr(unsigned long pc,
  * number in case of an error.  A positive return means unwinding is finished; 
  * don't try to fallback to dumping addresses on the stack. */
 static int unwind_frame(struct unwind_frame_info *frame,
+			struct task_struct *tsk,
 			struct _stp_module *m, struct _stp_section *s,
 			void *table, uint32_t table_len, int is_ehframe)
 {
@@ -619,7 +624,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
 		goto err;
 	}
 
-	fde = _stp_search_unwind_hdr(pc, m, s);
+	fde = _stp_search_unwind_hdr(pc, tsk, m, s);
 	dbug_unwind(1, "%s: fde=%lx\n", m->name, (unsigned long) fde);
 
 	/* found the fde, now set startLoc and endLoc */
@@ -629,7 +634,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
 			ptr = (const u8 *)(fde + 2);
 			ptrType = fde_pointer_type(cie, table, table_len);
 			startLoc = read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType);
-			startLoc = adjustStartLoc(startLoc, m, s, ptrType, is_ehframe);
+			startLoc = adjustStartLoc(startLoc, tsk, m, s, ptrType, is_ehframe);
 
 			dbug_unwind(2, "startLoc=%lx, ptrType=%s\n", startLoc, _stp_eh_enc_name(ptrType));
 			if (!(ptrType & DW_EH_PE_indirect))
@@ -660,7 +665,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
 
 			ptr = (const u8 *)(fde + 2);
 			startLoc = read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType);
-			startLoc = adjustStartLoc(startLoc, m, s, ptrType, is_ehframe);
+			startLoc = adjustStartLoc(startLoc, tsk, m, s, ptrType, is_ehframe);
 			dbug_unwind(2, "startLoc=%lx, ptrType=%s\n", startLoc, _stp_eh_enc_name(ptrType));
 			if (!startLoc)
 				continue;
@@ -902,18 +907,18 @@ static int unwind(struct unwind_frame_info *frame, struct task_struct *tsk)
 	if (UNW_PC(frame) == 0)
 		return -EINVAL;
 
-	m = _stp_mod_sec_lookup (pc, tsk, &s);
+	m = _stp_mod_sec_lookup (pc, tsk, &s, NULL);
 	if (unlikely(m == NULL)) {
 		dbug_unwind(1, "No module found for pc=%lx", pc);
 		return -EINVAL;
 	}
 
 	dbug_unwind(1, "trying debug_frame\n");
-	res = unwind_frame (frame, m, s, m->debug_frame,
+	res = unwind_frame (frame, tsk, m, s, m->debug_frame,
 			    m->debug_frame_len, 0);
 	if (res != 0) {
 	  dbug_unwind(1, "debug_frame failed: %d, trying eh_frame\n", res);
-	  res = unwind_frame (frame, m, s, m->eh_frame,
+	  res = unwind_frame (frame, tsk, m, s, m->eh_frame,
 			      m->eh_frame_len, 1);
 	}
 
diff --git a/tapset/context-symbols.stp b/tapset/context-symbols.stp
index 6cd4dcbb..38900196 100644
--- a/tapset/context-symbols.stp
+++ b/tapset/context-symbols.stp
@@ -91,7 +91,7 @@ function probemod:string () %{ /* pure */
 		*dst = 0;
 	} else if (CONTEXT->regs) {
 		struct _stp_module *m;
-		m = _stp_mod_sec_lookup (REG_IP(CONTEXT->regs), current, NULL);
+		m = _stp_mod_sec_lookup (REG_IP(CONTEXT->regs), current, NULL, NULL);
 		if (m && m->name)
 			strlcpy (THIS->__retvalue, m->name, MAXSTRINGLEN);
 		else
@@ -111,7 +111,7 @@ function probemod:string () %{ /* pure */
  */
 function modname:string (addr: long) %{ /* pure */
 	struct _stp_module *m;
-	m = _stp_mod_sec_lookup (THIS->addr, current, NULL);
+	m = _stp_mod_sec_lookup (THIS->addr, current, NULL, NULL);
 	if (m && m->name)
           strlcpy (THIS->__retvalue, m->name, MAXSTRINGLEN);
 	else
diff --git a/tapsets.cxx b/tapsets.cxx
index a5e2c7a0..e14cc496 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -3429,7 +3429,7 @@ dwarf_derived_probe_group::emit_module_init (systemtap_session& s)
   s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {";
   s.op->newline(1) << "struct stap_dwarf_probe *sdp = & stap_dwarf_probes[i];";
   s.op->newline() << "struct stap_dwarf_kprobe *kp = & stap_dwarf_kprobes[i];";
-  s.op->newline() << "unsigned long relocated_addr = _stp_module_relocate (sdp->module, sdp->section, sdp->address);";
+  s.op->newline() << "unsigned long relocated_addr = _stp_module_relocate (sdp->module, sdp->section, sdp->address, NULL);";
   s.op->newline() << "if (relocated_addr == 0) continue;"; // quietly; assume module is absent
   s.op->newline() << "probe_point = sdp->pp;"; // for error messages
   s.op->newline() << "if (sdp->return_p) {";
diff --git a/testsuite/buildok/vm.tracepoints.stp b/testsuite/buildok/vm.tracepoints.stp
new file mode 100644
index 00000000..488ca0fc
--- /dev/null
+++ b/testsuite/buildok/vm.tracepoints.stp
@@ -0,0 +1,31 @@
+#! stap -up4
+
+probe vm.kfree {
+        println(name)
+        printf("%-15s %-15p %-15s %-15p \n", execname(), call_site, caller_function, ptr)
+}
+
+probe vm.kmalloc {
+        println(name)
+        printf("%-15s %-15p %-15s %-15p %-15d %-15d %-15d %-15s \n", execname(), call_site, caller_function, ptr, bytes_req, bytes_alloc, gfp_flags, gfp_flag_name)
+}
+
+probe vm.kmem_cache_alloc {
+        println(name)
+        printf("%-15s %-15p %-15s %-15p %-15d %-15d %-15d %-15s \n", execname(), call_site, caller_function, ptr, bytes_req, bytes_alloc, gfp_flags, gfp_flag_name)
+}
+
+probe vm.kmalloc_node {
+        println(name)
+        printf("%-15s %-15p %-15s %-15p %-15d %-15d %-15d %-15s \n", execname(), call_site, caller_function, ptr, bytes_req, bytes_alloc, gfp_flags, gfp_flag_name)
+}
+
+probe vm.kmem_cache_alloc_node {
+        println(name)
+        printf("%-15s %-15p %-15s %-15p %-15d %-15d %-15d %-15s \n", execname(), call_site, caller_function, ptr, bytes_req, bytes_alloc, gfp_flags, gfp_flag_name)
+}
+
+probe vm.kmem_cache_free {
+        println(name)
+        printf("%-15s %-15p %-15s %-15p \n", execname(), call_site, caller_function, ptr)
+}
diff --git a/testsuite/systemtap.examples/memory/vm.tracepoints.meta b/testsuite/systemtap.examples/memory/vm.tracepoints.meta
new file mode 100644
index 00000000..9fdb73f6
--- /dev/null
+++ b/testsuite/systemtap.examples/memory/vm.tracepoints.meta
@@ -0,0 +1,13 @@
+title: Collect slab allocation statistics
+name: vm.tracepoints.stp
+version: 1.0
+author: Rajasekhar
+keywords: memory slab allocator
+subsystem: memory
+status: production
+exit: user-controlled
+output: sorted-list
+scope: system-wide
+description: The script will probe all memory slab/slub allocations and collects information about the size of the object (bytes requested) and user-space process in execution. When run over a period of time, it helps to correlate kernel-space memory consumption owing to user-space processes.
+test_check: stap -p4 vm.tracepoints.stp
+test_installcheck: stap vm.tracepoints.stp -c "sleep 10"
diff --git a/testsuite/systemtap.examples/memory/vm.tracepoints.stp b/testsuite/systemtap.examples/memory/vm.tracepoints.stp
new file mode 100644
index 00000000..07cee6f5
--- /dev/null
+++ b/testsuite/systemtap.examples/memory/vm.tracepoints.stp
@@ -0,0 +1,18 @@
+global slabs
+
+probe vm.kmem_cache_alloc {
+	slabs [execname(), bytes_req]<<<1
+}
+
+probe timer.ms(10000)
+{
+	dummy = "";
+	foreach ([name, bytes] in slabs) {
+		if (dummy != name)
+			printf("\nProcess:%s\n", name);
+        	printf("Slab_size:%d\tCount:%d\n", bytes, @count(slabs[name, bytes]));
+		dummy = name;
+	}
+	delete slabs
+	printf("\n-------------------------------------------------------\n\n")
+}