feat: add crash stack snapshots and context menu annotations

kernel/src/Api/BuildNo.hpp

@@ -12,4 +12,4 @@
 
 #pragma once
 
-#define MONTAUK_BUILD_NUMBER 106
+#define MONTAUK_BUILD_NUMBER 108

kernel/src/Api/CrashReportSyscall.hpp

@@ -34,6 +34,9 @@ namespace montauk::abi {
         out->codeSegment = rep.codeSegment;
         out->flags = rep.flags;
         out->stackSegment = rep.stackSegment;
+        out->stackWordCount = rep.stackWordCount;
+        for (int i = 0; i < rep.stackWordCount && i < CrashReport::StackSnapshotWords; i++)
+            out->stackWords[i] = rep.stackWords[i];
         out->pfPresent = rep.pfPresent;
         out->pfWrite = rep.pfWrite;
         out->pfUser = rep.pfUser;

kernel/src/Api/Syscall.hpp

@@ -780,6 +780,8 @@ namespace montauk::abi {
         uint64_t codeSegment;
         uint64_t flags;
         uint64_t stackSegment;
+        uint64_t stackWords[8];
+        uint8_t stackWordCount;
         uint8_t pfPresent : 1;
         uint8_t pfWrite : 1;
         uint8_t pfUser : 1;

kernel/src/Hal/IDT.cpp

@@ -127,6 +127,21 @@ namespace Hal {
             rep.stackPointer = regs->SP;
             rep.stackSegment = regs->SS;
 
+            // An indirect CALL pushes its real continuation address before a
+            // bad target faults on instruction fetch. Preserve a small stack
+            // snapshot while the dying process address space is still active;
+            // stackWords[0] will usually identify the caller even when RIP is
+            // corrupted data and cannot itself be symbolicated.
+            constexpr uint64_t snapshotBytes =
+                CrashReport::StackSnapshotWords * sizeof(uint64_t);
+            if (Memory::VMM::Paging::IsUserRangeAccessible(
+                    proc->pml4Phys, regs->SP, snapshotBytes, false)) {
+                auto* userStack = (const volatile uint64_t*)regs->SP;
+                for (int word = 0; word < CrashReport::StackSnapshotWords; word++)
+                    rep.stackWords[word] = userStack[word];
+                rep.stackWordCount = CrashReport::StackSnapshotWords;
+            }
+
             if (i == 0x0E) {
                 // Page fault: read CR2 for faulting address
                 asm volatile("mov %%cr2, %0" : "=r"(rep.faultingAddress));

kernel/src/Sched/CrashReport.hpp

@@ -11,6 +11,7 @@
 namespace CrashReport {
 
 static constexpr int MaxReports = 8;
+static constexpr int StackSnapshotWords = 8;
 
 struct Report {
     int pid;
@@ -24,6 +25,8 @@ struct Report {
     uint64_t codeSegment;
     uint64_t flags;
     uint64_t stackSegment;
+    uint64_t stackWords[StackSnapshotWords];
+    uint8_t stackWordCount;
 
     // Page fault error code bits (vector 0xE / page fault only)
     uint8_t pfPresent : 1;