Increase stack size to 20 pages

This workaround bad codegen in debug mode on libfat's GenericIterator.

fs/src/main.rs

@@ -1,6 +1,8 @@
-//! Clock applet
+//! Filesystem sysmodule
 //!
-//! Show the current time in the bottom left corner of the screen.
+//! High level access to filesystem and disks.
+//!
+//! NOTE: This need at least 16 pages of stack to run in debug builds because of bad codegen on the compiler side for libfat's iterators.
 
 #![no_std]
 // rustc warnings

kernel/src/main.rs

@@ -144,12 +144,12 @@ fn main() {
 
                 let ep = elf_loader::load_builtin(&mut pmemlock, &mapped_module);
 
-                let stack = pmemlock.find_available_space(9 * PAGE_SIZE)
+                let stack = pmemlock.find_available_space(20 * PAGE_SIZE)
                     .unwrap_or_else(|_| panic!("Cannot create a stack for process {:?}", proc));
                 pmemlock.guard(stack, PAGE_SIZE, MemoryType::Reserved).unwrap();
-                pmemlock.create_regular_mapping(stack + PAGE_SIZE, 8 * PAGE_SIZE, MemoryType::Stack, MappingAccessRights::u_rw()).unwrap();
+                pmemlock.create_regular_mapping(stack + PAGE_SIZE, 19 * PAGE_SIZE, MemoryType::Stack, MappingAccessRights::u_rw()).unwrap();
 
-                (VirtualAddress(ep), stack + 9 * PAGE_SIZE)
+                (VirtualAddress(ep), stack + 20 * PAGE_SIZE)
         };
         let thread = ThreadStruct::new(&proc, ep, sp, 0)
             .expect("failed creating thread for service");