commit 5abded54b
Author: Stan Cox <scox@redhat.com>
Date:   Fri Jan 28 15:28:27 2022 -0500

    Attempt to access string in userspace if kernel access fails
    
    Add kernel_or_user_string_quoted(_utf16 _utf32) tapsets to handle
    situations where a kernelspace access was assumed but string is in
    userspace.

diff --git a/tapset/linux/conversions.stp b/tapset/linux/conversions.stp
index 82f535f6c..d3d3a0b5a 100644
--- a/tapset/linux/conversions.stp
+++ b/tapset/linux/conversions.stp
@@ -72,6 +72,17 @@ function kernel_string_quoted:string (addr:long)
 		    (unsigned long)(uintptr_t)STAP_ARG_addr);
 %}
 
+/**
+ * sfunction kernel_or_user_string_quoted - Retrieves and quotes string from kernel or user memory
+ *
+ * @addr: the kernel or user memory address to retrieve the string from
+ *
+ * Similar to kernel_string_quoted except user memory is a fallback method
+ */
+function kernel_or_user_string_quoted:string (addr:long) {
+  try { return string_quoted(kernel_string(addr)) } catch { return string_quoted(user_string(addr)) }
+}
+
 /**
  * sfunction kernel_string_n - Retrieves string of given length from kernel memory
  * @addr: The kernel address to retrieve the string from
@@ -160,6 +171,16 @@ function kernel_string_quoted_utf32:string (addr:long) {
   try { return string_quoted(kernel_string_utf32(addr)) } catch { return sprintf("0x%x", addr) }
 }
 
+/**
+ * sfunction kernel_or_user_string_quoted_utf32 - Retrieves and quotes UTF-32 string from kernel or user memory
+ *
+ * @addr: the kernel or user memory address to retrieve the string from
+ *
+ * Similar to kernel_string_quoted_utf32 except user memory is a fallback method
+ */
+function kernel_or_user_string_quoted_utf32:string (addr:long) {
+ try { return string_quoted(kernel_string_utf32(addr)) } catch { return string_quoted(user_string_utf32(addr)) }
+}
 
 /**
  * sfunction kernel_string_utf16 - Retrieves UTF-16 string from kernel memory
@@ -242,6 +263,17 @@ function kernel_string_quoted_utf16:string (addr:long) {
   try { return string_quoted(kernel_string_utf16(addr)) } catch { return sprintf("0x%x", addr) }
 }
 
+/**
+ * sfunction kernel_or_user_string_quoted_utf16 - Retrieves and quotes UTF-16 string from kernel or user memory
+ *
+ * @addr: the kernel or user memory address to retrieve the string from
+ *
+ * Similar to kernel_string_quoted_utf16 except uses user memory as a fallback method
+ */
+function kernel_or_user_string_quoted_utf16:string (addr:long) {
+ try { return string_quoted(kernel_string_utf16(addr)) } catch { return string_quoted(user_string_utf16(addr)) }
+}
+
 
 /**
  * sfunction kernel_long - Retrieves a long value stored in kernel memory
diff --git a/tapsets.cxx b/tapsets.cxx
index 8fc5146e2..8b8f1cad5 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -3757,7 +3757,7 @@ dwarf_pretty_print::print_chars (Dwarf_Die* start_type, target_symbol* e,
       return false;
     }
 
-  string function = userspace_p ? "user_string_quoted" : "kernel_string_quoted";
+  string function = userspace_p ? "user_string_quoted" : "kernel_or_user_string_quoted";
   Dwarf_Word size = (Dwarf_Word) -1;
   dwarf_formudata (dwarf_attr_integrate (&type, DW_AT_byte_size, &attr), &size);
   switch (size)