tests: Add tests which triggers stack canary

The change to `canary.rs` it to be able to detect the stack overflow.

src/canary.rs

@@ -78,10 +78,7 @@ impl Canary {
             // When measuring stack consumption, we have to color the whole stack.
             stack_available as usize
         } else {
-            // We consider >90% stack usage a potential stack overflow, but don't go beyond 1 kb
-            // since filling a lot of RAM is slow (and 1 kb should be "good enough" for what we're
-            // doing).
-            round_up(1024.min(stack_available / 10), 4) as usize
+            round_up(stack_available / 10, 4) as usize
         };
 
         log::debug!(

tests/snapshot.rs

@@ -105,6 +105,7 @@ fn truncate_output(probe_run_output: String) -> String {
 #[case::panic_verbose("panic-rzcobs --verbose", false)]
 #[case::unsuccessful_run_can_suppress_backtrace("panic-rzcobs --backtrace=never", false)]
 #[case::stack_overflow_can_suppress_backtrace("overflow-rzcobs --backtrace=never", false)]
+#[case::canary("overflow-no-flip-link", false)]
 #[serial]
 #[ignore = "requires the target hardware to be present"]
 fn snapshot_test(#[case] args: &str, #[case] success: bool) {

tests/snapshots/snapshot__case_4_stack_overflow_is_reported_as_such.snap

@@ -1,6 +1,6 @@
 ---
 source: tests/snapshot.rs
-assertion_line: 113
+assertion_line: 114
 expression: run_result.output
 
 ---
@@ -23,6 +23,7 @@ ack(m=9, n=0, SP=2000ba18)
 ack(m=8, n=1, SP=200079f8)
 ack(m=8, n=0, SP=200039d8)
 ────────────────────────────────────────────────────────────────────────────────
+(HOST) WARN  program has used at least 240.62/254.93 KiB (94.4%) of stack space
 stack backtrace:
    0: HardFaultTrampoline
       <exception entry>

tests/snapshots/snapshot__case_8_stack_overflow_can_suppress_backtrace.snap

@@ -1,6 +1,6 @@
 ---
 source: tests/snapshot.rs
-assertion_line: 113
+assertion_line: 114
 expression: run_result.output
 
 ---
@@ -23,5 +23,6 @@ ack(m=9, n=0, SP=2000ba18)
 ack(m=8, n=1, SP=200079f8)
 ack(m=8, n=0, SP=200039d8)
 ────────────────────────────────────────────────────────────────────────────────
+(HOST) WARN  program has used at least 240.62/254.93 KiB (94.4%) of stack space
 (HOST) ERROR the program has overflowed its stack
 

tests/snapshots/snapshot__case_9_canary.snap

@@ -0,0 +1,33 @@
+---
+source: tests/snapshot.rs
+assertion_line: 114
+expression: run_result.output
+
+---
+(HOST) INFO  flashing program (2 pages / 8.00 KiB)
+(HOST) INFO  success!
+────────────────────────────────────────────────────────────────────────────────
+ack(m=10, n=10, SP=2003bfd8)
+ack(m=10, n=9, SP=20037fb8)
+ack(m=10, n=8, SP=20033f98)
+ack(m=10, n=7, SP=2002ff78)
+ack(m=10, n=6, SP=2002bf58)
+ack(m=10, n=5, SP=20027f38)
+ack(m=10, n=4, SP=20023f18)
+ack(m=10, n=3, SP=2001fef8)
+ack(m=10, n=2, SP=2001bed8)
+ack(m=10, n=1, SP=20017eb8)
+ack(m=10, n=0, SP=20013e98)
+ack(m=9, n=1, SP=2000fe78)
+ack(m=9, n=0, SP=2000be58)
+ack(m=8, n=1, SP=20007e38)
+ack(m=8, n=0, SP=20003e18)
+────────────────────────────────────────────────────────────────────────────────
+(HOST) WARN  program has used at least 240.62/254.93 KiB (94.4%) of stack space
+(HOST) WARN  data segments might be corrupted due to stack overflow
+stack backtrace:
+   0: HardFaultTrampoline
+      <exception entry>
+(HOST) WARN  call stack was corrupted; unwinding could not be completed
+(HOST) ERROR the program has overflowed its stack
+