stack: increase size of the interrupt and small syscall stack in debu…

…g mode

When building OSv with newer GCC (>= 12) in debug mode, the interrupt
handler running on dedicated stack needs more than 1 page otherwise it
causes overflow. Similarly, the code setting up large syscall stack,
running on small 2K stack runs of of space as well.

To fix this, we increase the interrupt stack size to 8K and small
syscall stack size to 8K when building in debug mode (#ifndef NDEBUG).

Ideally, in long term we should implement some canary-based logic to
detect interrupt stack overflow as the issue #1339 explains.

Ref #1339

Signed-off-by: Waldemar Kozaczuk <[email protected]>

arch/x64/arch-cpu.hh

@@ -73,7 +73,11 @@ struct arch_cpu {
 };
 
 struct arch_thread {
+#ifndef NDEBUG
+    char interrupt_stack[4096*2] __attribute__((aligned(16)));
+#else
     char interrupt_stack[4096] __attribute__((aligned(16)));
+#endif
     char exception_stack[4096*4] __attribute__((aligned(16)));
 };
 

arch/x64/arch-switch.hh

@@ -29,7 +29,11 @@
 // to detect potential tiny stack overflow.
 // All application threads pre-allocate tiny syscall stack so there
 // is a tiny penalty with this solution.
+#ifndef NDEBUG
+#define TINY_SYSCALL_STACK_SIZE 2*4096
+#else
 #define TINY_SYSCALL_STACK_SIZE 2048
+#endif
 #define TINY_SYSCALL_STACK_DEPTH (TINY_SYSCALL_STACK_SIZE - SYSCALL_STACK_RESERVED_SPACE_SIZE)
 //
 // The large syscall stack is setup and switched to on first