Add context argument to crash dump functions to preserve register state

src/coreclr/nativeaot/Runtime/unix/HardwareExceptions.cpp

@@ -559,7 +559,7 @@ void SIGSEGVHandler(int code, siginfo_t *siginfo, void *context)
         RestoreSignalHandler(code, &g_previousSIGSEGV);
     }
 
-    PalCreateCrashDumpIfEnabled(code, siginfo);
+    PalCreateCrashDumpIfEnabled(code, siginfo, context);
 }
 
 // Handler for the SIGFPE signal
@@ -581,7 +581,7 @@ void SIGFPEHandler(int code, siginfo_t *siginfo, void *context)
         RestoreSignalHandler(code, &g_previousSIGFPE);
     }
 
-    PalCreateCrashDumpIfEnabled(code, siginfo);
+    PalCreateCrashDumpIfEnabled(code, siginfo, context);
 }
 
 // Initialize hardware exception handling

src/coreclr/nativeaot/Runtime/unix/PalCreateDump.cpp

@@ -346,6 +346,19 @@ CreateCrashDump(
 
 #endif // !defined(HOST_MACCATALYST) && !defined(HOST_IOS) && !defined(HOST_TVOS)
 
+// Helper function to prevent compiler from optimizing away a variable
+#if defined(__llvm__)
+__attribute__((noinline, optnone))
+#else
+__attribute__((noinline, optimize("O0")))
+#endif
+static void DoNotOptimize(const void* p)
+{
+    // This function takes the address of a variable to ensure
+    // it's preserved and available in crash dumps
+    (void)p;
+}
+
 /*++
 Function:
   PalCreateCrashDumpIfEnabled
@@ -355,13 +368,17 @@ CreateCrashDump(
 Parameters:
     signal - POSIX signal number or 0
     siginfo - signal info or nullptr
+    context - signal context or nullptr
     exceptionRecord - address of exception record or nullptr
 
 (no return value)
 --*/
 void
-PalCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, void* exceptionRecord)
+PalCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, void* context, void* exceptionRecord)
 {
+    // Preserve context pointer to prevent optimization
+    DoNotOptimize(&context);
+
 #if !defined(HOST_MACCATALYST) && !defined(HOST_IOS) && !defined(HOST_TVOS)
     // If enabled, launch the create minidump utility and wait until it completes
     if (g_argvCreateDump[0] != nullptr)
@@ -454,13 +471,13 @@ PalCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, void* exceptionRecor
 void
 PalCreateCrashDumpIfEnabled()
 {
-    PalCreateCrashDumpIfEnabled(SIGABRT, nullptr, nullptr);
+    PalCreateCrashDumpIfEnabled(SIGABRT, nullptr, nullptr, nullptr);
 }
 
 void
 PalCreateCrashDumpIfEnabled(void* pExceptionRecord)
 {
-    PalCreateCrashDumpIfEnabled(SIGABRT, nullptr, pExceptionRecord);
+    PalCreateCrashDumpIfEnabled(SIGABRT, nullptr, nullptr, pExceptionRecord);
 }
 
 /*++

src/coreclr/nativeaot/Runtime/unix/PalCreateDump.h

@@ -7,5 +7,5 @@
 
 extern bool PalCreateDumpInitialize();
 extern void PalCreateCrashDumpIfEnabled();
-extern void PalCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo = nullptr, void* exceptionRecord = nullptr);
+extern void PalCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo = nullptr, void* context = nullptr, void* exceptionRecord = nullptr);
 extern void PalCreateCrashDumpIfEnabled(void* pExceptionRecord);

src/coreclr/pal/src/exception/signal.cpp

@@ -422,7 +422,7 @@ static void invoke_previous_action(struct sigaction* action, int code, siginfo_t
         if (signalRestarts)
         {
             // This signal mustn't be ignored because it will be restarted.
-            PROCAbort(code, siginfo);
+            PROCAbort(code, siginfo, context);
         }
         return;
     }
@@ -433,7 +433,7 @@ static void invoke_previous_action(struct sigaction* action, int code, siginfo_t
             // Shutdown and create the core dump before we restore the signal to the default handler.
             PROCNotifyProcessShutdown(IsRunningOnAlternateStack(context));
 
-            PROCCreateCrashDumpIfEnabled(code, siginfo, true);
+            PROCCreateCrashDumpIfEnabled(code, siginfo, context, true);
 
             // Restore the original and restart h/w exception.
             restore_signal(code, action);
@@ -444,7 +444,7 @@ static void invoke_previous_action(struct sigaction* action, int code, siginfo_t
         {
             // We can't invoke the original handler because returning from the
             // handler doesn't restart the exception.
-            PROCAbort(code, siginfo);
+            PROCAbort(code, siginfo, context);
         }
     }
     else if (IsSaSigInfo(action))
@@ -462,7 +462,7 @@ static void invoke_previous_action(struct sigaction* action, int code, siginfo_t
 
     PROCNotifyProcessShutdown(IsRunningOnAlternateStack(context));
 
-    PROCCreateCrashDumpIfEnabled(code, siginfo, true);
+    PROCCreateCrashDumpIfEnabled(code, siginfo, context, true);
 }
 
 /*++
@@ -655,7 +655,7 @@ static void sigsegv_handler(int code, siginfo_t *siginfo, void *context)
             {
 #if defined(TARGET_TVOS)
                 (void)!write(STDERR_FILENO, StackOverflowMessage, sizeof(StackOverflowMessage) - 1);
-                PROCAbort(SIGSEGV, siginfo);
+                PROCAbort(SIGSEGV, siginfo, context);
 #else // TARGET_TVOS
                 size_t handlerStackTop = __sync_val_compare_and_swap((size_t*)&g_stackOverflowHandlerStack, (size_t)g_stackOverflowHandlerStack, 0);
                 if (handlerStackTop == 0)
@@ -682,7 +682,7 @@ static void sigsegv_handler(int code, siginfo_t *siginfo, void *context)
 
                 if (SwitchStackAndExecuteHandler(code | StackOverflowFlag, siginfo, context, (size_t)handlerStackTop))
                 {
-                    PROCAbort(SIGSEGV, siginfo);
+                    PROCAbort(SIGSEGV, siginfo, context);
                 }
                 (void)!write(STDERR_FILENO, StackOverflowHandlerReturnedMessage, sizeof(StackOverflowHandlerReturnedMessage) - 1);
 #endif // TARGET_TVOS
@@ -851,7 +851,7 @@ static void sigterm_handler(int code, siginfo_t *siginfo, void *context)
         DWORD val = 0;
         if (enableDumpOnSigTerm.IsSet() && enableDumpOnSigTerm.TryAsInteger(10, val) && val == 1)
         {
-            PROCCreateCrashDumpIfEnabled(code, siginfo, false);
+            PROCCreateCrashDumpIfEnabled(code, siginfo, context, false);
         }
     }
 

src/coreclr/pal/src/include/pal/process.h

@@ -152,14 +152,15 @@ BOOL PROCAbortInitialize();
 Parameters:
   signal - POSIX signal number
   siginfo - POSIX signal info
+  context - signal context or nullptr
 
   Does not return
 --*/
 #if !defined(HOST_ARM)  // PAL_NORETURN produces broken unwinding information for this method
                         // making crash dumps impossible to analyze
 PAL_NORETURN
 #endif
-VOID PROCAbort(int signal = SIGABRT, siginfo_t* siginfo = nullptr);
+VOID PROCAbort(int signal = SIGABRT, siginfo_t* siginfo = nullptr, void* context = nullptr);
 
 /*++
 Function:
@@ -182,11 +183,12 @@ VOID PROCNotifyProcessShutdown(bool isExecutingOnAltStack = false);
 Parameters:
   signal - POSIX signal number
   siginfo - POSIX signal info or nullptr
+  context - signal context or nullptr
   serialize - allow only one thread to generate core dump
 
 (no return value)
 --*/
-VOID PROCCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, bool serialize);
+VOID PROCCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, void* context, bool serialize);
 
 #ifdef __cplusplus
 }

src/coreclr/pal/src/thread/process.cpp

@@ -2706,6 +2706,15 @@ PAL_GenerateCoreDump(
     return result;
 }
 
+// Helper function to prevent compiler from optimizing away a variable
+__attribute__((noinline,NOOPT_ATTRIBUTE))
+static void DoNotOptimize(const void* p)
+{
+    // This function takes the address of a variable to ensure
+    // it's preserved and available in crash dumps
+    (void)p;
+}
+
 /*++
 Function:
   PROCCreateCrashDumpIfEnabled
@@ -2716,23 +2725,30 @@ PAL_GenerateCoreDump(
 Parameters:
   signal - POSIX signal number
   siginfo - POSIX signal info or nullptr
+  context - signal context or nullptr
   serialize - allow only one thread to generate core dump
 
 (no return value)
 --*/
 #ifdef HOST_ANDROID
 #include <minipal/log.h>
 VOID
-PROCCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, bool serialize)
+PROCCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, void* context, bool serialize)
 {
+    // Preserve context pointer to prevent optimization
+    DoNotOptimize(&context);
+
     // TODO: Dump all managed threads callstacks into logcat and/or file?
     // TODO: Dump stress log into logcat and/or file when enabled?
     minipal_log_write_fatal("Aborting process.\n");
 }
 #else
 VOID
-PROCCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, bool serialize)
+PROCCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, void* context, bool serialize)
 {
+    // Preserve context pointer to prevent optimization
+    DoNotOptimize(&context);
+
     // If enabled, launch the create minidump utility and wait until it completes
     if (!g_argvCreateDump.empty())
     {
@@ -2809,19 +2825,20 @@ PROCCreateCrashDumpIfEnabled(int signal, siginfo_t* siginfo, bool serialize)
 
 Parameters:
   signal - POSIX signal number
+  context - signal context or nullptr
 
   Does not return
 --*/
 #if !defined(HOST_ARM)
 PAL_NORETURN
 #endif
 VOID
-PROCAbort(int signal, siginfo_t* siginfo)
+PROCAbort(int signal, siginfo_t* siginfo, void* context)
 {
     // Do any shutdown cleanup before aborting or creating a core dump
     PROCNotifyProcessShutdown();
 
-    PROCCreateCrashDumpIfEnabled(signal, siginfo, true);
+    PROCCreateCrashDumpIfEnabled(signal, siginfo, context, true);
 
     // Restore all signals; the SIGABORT handler to prevent recursion and
     // the others to prevent multiple core dumps from being generated.