Try to fix uffd failing test

bytecodealliance · Jun 10, 2021 · 88128ed · 88128ed
1 parent b7ca4c9
commit 88128ed
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Showing 2 changed files with 22 additions and 8 deletions.
diff --git a/crates/runtime/src/instance/allocator/pooling/uffd.rs b/crates/runtime/src/instance/allocator/pooling/uffd.rs
@@ -156,6 +156,7 @@ struct FaultLocator {
     instances_start: usize,
     instance_size: usize,
     max_instances: usize,
+    unguarded_memories_start: usize,
     memories_start: usize,
     memories_end: usize,
     memory_size: usize,
@@ -167,14 +168,16 @@ impl FaultLocator {
         let instances_start = instances.mapping.as_ptr() as usize;
         let memories_start =
             instances.memories.mapping.as_ptr() as usize + instances.memories.initial_memory_offset;
-        let memories_end = memories_start + instances.memories.mapping.len();
+        let memories_end =
+            instances.memories.mapping.as_ptr() as usize + instances.memories.mapping.len();
 
         // Should always have instances
         debug_assert!(instances_start != 0);
 
         Self {
             instances_start,
             instance_size: instances.instance_size,
+            unguarded_memories_start: instances.memories.mapping.as_ptr() as usize,
             max_instances: instances.max_instances,
             memories_start,
             memories_end,
@@ -345,7 +348,7 @@ fn fault_handler_thread(uffd: Uffd, locator: FaultLocator) -> Result<()> {
 
                 let (start, end) = (start as usize, end as usize);
 
-                if start == locator.memories_start && end == locator.memories_end {
+                if start == locator.unguarded_memories_start && end == locator.memories_end {
                     break;
                 } else {
                     panic!("unexpected memory region unmapped");
@@ -438,7 +441,9 @@ mod test {
         PoolingAllocationStrategy, VMSharedSignatureIndex,
     };
     use std::sync::Arc;
-    use wasmtime_environ::{entity::PrimaryMap, wasm::Memory, MemoryPlan, MemoryStyle, Module};
+    use wasmtime_environ::{
+        entity::PrimaryMap, wasm::Memory, MemoryPlan, MemoryStyle, Module, Tunables,
+    };
 
     #[cfg(target_pointer_width = "64")]
     #[test]
@@ -456,13 +461,16 @@ mod test {
             table_elements: 0,
             memory_pages: 2,
         };
-        let instance_limits = InstanceLimits {
-            count: 3,
-            memory_reservation_size: (WASM_PAGE_SIZE * 10) as u64,
+        let instance_limits = InstanceLimits { count: 3 };
+        let tunables = Tunables {
+            static_memory_bound: 10,
+            static_memory_offset_guard_size: 0,
+            guard_before_linear_memory: false,
+            ..Tunables::default()
         };
 
-        let instances =
-            InstancePool::new(&module_limits, &instance_limits).expect("should allocate");
+        let instances = InstancePool::new(&module_limits, &instance_limits, &tunables)
+            .expect("should allocate");
 
         let locator = FaultLocator::new(&instances);
 

diff --git a/tests/all/memory.rs b/tests/all/memory.rs
@@ -240,6 +240,12 @@ unsafe fn assert_faults(ptr: *mut u8) {
     use std::io::Error;
     #[cfg(unix)]
     {
+        // I think things get real weird with uffd since there's a helper thread
+        // that's not cloned with `fork` below. Just skip this test for uffd
+        // since it's covered by tests elsewhere.
+        if cfg!(target_os = "linux") && cfg!(feature = "uffd") {
+            return;
+        }
         // There's probably a faster way to do this here, but, uh, when in rome?
         match libc::fork() {
             0 => {