linuxkm/linuxkm_wc_port.h and linuxkm/module_hooks.c: remove WOLFSSL_DEBUG_BACKTRACE_ERROR_CODES gate around setup for wolfssl_linuxkm_pie_redirect_table.dump_stack.

linuxkm/module_hooks.c: in wc_linuxkm_relax_long_loop(), use cpu_relax() as a fallback when non-preemptible.

linuxkm/linuxkm_wc_port.h

@@ -1072,9 +1072,7 @@
 
         #endif /* !WOLFCRYPT_ONLY && !NO_CERTS */
 
-        #ifdef WOLFSSL_DEBUG_BACKTRACE_ERROR_CODES
         typeof(dump_stack) *dump_stack;
-        #endif
 
         #ifdef CONFIG_ARM64
         #ifndef CONFIG_ARCH_TEGRA
@@ -1345,9 +1343,7 @@
 
     #endif /* !WOLFCRYPT_ONLY && !NO_CERTS */
 
-    #ifdef WOLFSSL_DEBUG_BACKTRACE_ERROR_CODES
         #define dump_stack WC_PIE_INDIRECT_SYM(dump_stack)
-    #endif
 
     #undef preempt_count /* just in case -- not a macro on x86. */
     #define preempt_count WC_PIE_INDIRECT_SYM(preempt_count)
@@ -1729,4 +1725,13 @@
         #error unexpected BITS_PER_LONG value.
 #endif
 
+/* WC_DUMP_BACKTRACE_NONDEBUG is intended to dump a backtrace only if it hasn't
+ * already been dumped by the called function.
+ */
+#if defined(WOLFSSL_DEBUG_TRACE_ERROR_CODES) && defined(WOLFSSL_DEBUG_BACKTRACE_ERROR_CODES)
+    #define WC_DUMP_BACKTRACE_NONDEBUG WC_DO_NOTHING
+#else
+    #define WC_DUMP_BACKTRACE_NONDEBUG dump_stack()
+#endif
+
 #endif /* LINUXKM_WC_PORT_H */

linuxkm/module_hooks.c

@@ -297,8 +297,10 @@ void wc_linuxkm_relax_long_loop(void) {
              */
         }
         #endif
+        return;
     }
     #endif
+    cpu_relax();
 }
 
 #if defined(WC_LINUXKM_WOLFENTROPY_IN_GLUE_LAYER)
@@ -1475,9 +1477,7 @@ static int set_up_wolfssl_linuxkm_pie_redirect_table(void) {
 #endif /* OPENSSL_EXTRA || OPENSSL_EXTRA_X509_SMALL */
 #endif /* !WOLFCRYPT_ONLY && !NO_CERTS */
 
-#ifdef WOLFSSL_DEBUG_BACKTRACE_ERROR_CODES
     wolfssl_linuxkm_pie_redirect_table.dump_stack = dump_stack;
-#endif
 
     wolfssl_linuxkm_pie_redirect_table.preempt_count = my_preempt_count;
 #ifndef _raw_spin_lock_irqsave