diff --git a/.cargo/android-runner.sh b/.cargo/android-runner.sh
index cfd908bf..23b55b85 100755
--- a/.cargo/android-runner.sh
+++ b/.cargo/android-runner.sh
@@ -10,4 +10,4 @@ TARGET=$(printf '%s' "$BINARY" | sed -E 's#(.*/)?target/([^/]+)/.*#\2#')
 # Make sure to run the following to copy the test helper binary over.
 # cargo run --target "$TARGET" --bin test
 adb push "$BINARY" "/data/local/$BINARY"
-adb shell "chmod 777 /data/local/$BINARY && env TEST_HELPER=/data/local/target/$TARGET/debug/test /data/local/$BINARY" "$@"
+adb shell "chmod 777 /data/local/$BINARY && env RUST_BACKTRACE='$RUST_BACKTRACE' TEST_HELPER=/data/local/target/$TARGET/debug/test /data/local/$BINARY" "$@"
diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index 99d6af7f..5be005ba 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -39,12 +39,23 @@ fn build_command() -> Command {
     cmd
 }
 
+/// Must be taken by tests that use ptrace() to avoid racing on attaching to the parent,
+/// leading to random failures.
+static PTRACE_PARENT_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
 #[allow(unused)]
 pub fn spawn_child(command: &str, args: &[&str]) {
     let mut cmd = build_command();
     cmd.arg(command).args(args);
 
-    let child = cmd.output().expect("failed to execute child");
+    let child = {
+        // Panicking is fine as far as ptrace is concerned,
+        // no need to poison other tests.
+        let _guard = PTRACE_PARENT_LOCK
+            .lock()
+            .unwrap_or_else(|poisoned| poisoned.into_inner());
+        cmd.output().expect("failed to execute child")
+    };
 
     println!("Child output:");
     println!("===stdout===");
diff --git a/tests/ptrace_dumper.rs b/tests/ptrace_dumper.rs
index 75be7002..cdbb6f79 100644
--- a/tests/ptrace_dumper.rs
+++ b/tests/ptrace_dumper.rs
@@ -12,7 +12,6 @@ use {
         mem::size_of,
         os::unix::process::ExitStatusExt,
         ptr,
-        sync::Mutex,
     },
 };
 
@@ -36,22 +35,13 @@ macro_rules! assert_no_soft_errors(($n: ident, $e: expr) => {{
     __result
 }});
 
-static GLOBAL_LOCK: Mutex<()> = Mutex::new(());
-
-macro_rules! one_at_a_time(() => {
-    let _guard_ = GLOBAL_LOCK.lock().unwrap_or_else(|e| e.into_inner());
-});
-
 #[test]
 fn setup() {
-    one_at_a_time!();
-
     spawn_child("setup", &[]);
 }
 
 #[test]
 fn thread_list_from_child() {
-    one_at_a_time!();
     // Child spawns and looks in the parent (== this process) for its own thread-ID
 
     let (tx, rx) = std::sync::mpsc::sync_channel(1);
@@ -110,8 +100,6 @@ fn thread_list_from_child() {
 
 #[test]
 fn thread_list_from_parent() {
-    one_at_a_time!();
-
     let num_of_threads = 5;
     let mut child = start_child_and_wait_for_threads(num_of_threads);
     let pid = child.id() as i32;
@@ -187,23 +175,17 @@ fn thread_list_from_parent() {
 #[test]
 // Ensure that the linux-gate VDSO is included in the mapping list.
 fn mappings_include_linux_gate() {
-    one_at_a_time!();
-
     spawn_child("mappings_include_linux_gate", &[]);
 }
 
 #[test]
 fn linux_gate_mapping_id() {
-    one_at_a_time!();
-
     disabled_on_ci_and_android!();
     spawn_child("linux_gate_mapping_id", &[]);
 }
 
 #[test]
 fn merges_mappings() {
-    one_at_a_time!();
-
     let page_size = unsafe { libc::sysconf(libc::_SC_PAGESIZE) };
     assert!(page_size > 0);
     let page_size = usize::try_from(page_size).unwrap();
@@ -256,8 +238,6 @@ fn merges_mappings() {
 // Ensure that the linux-gate VDSO is included in the mapping list.
 #[test]
 fn file_id() {
-    one_at_a_time!();
-
     disabled_on_ci_and_android!();
     spawn_child("file_id", &[]);
 }
@@ -265,8 +245,6 @@ fn file_id() {
 #[cfg(not(target_os = "android"))]
 #[test]
 fn finds_mappings() {
-    one_at_a_time!();
-
     spawn_child(
         "find_mappings",
         &[
@@ -278,8 +256,6 @@ fn finds_mappings() {
 
 #[test]
 fn copies_from_process_self() {
-    one_at_a_time!();
-
     disabled_on_ci_and_android!();
 
     let stack_var: libc::c_long = 0x11223344;
@@ -296,8 +272,6 @@ fn copies_from_process_self() {
 // Ensures that we sanitize the stack properly
 #[test]
 fn sanitizes_stack_copies() {
-    one_at_a_time!();
-
     let num_of_threads = 1;
     let mut child = start_child_and_return(&["spawn_alloc_wait"]);
     let pid = child.id() as i32;