diff --git a/meson.build b/meson.build
index 917695d..793a9df 100644
--- a/meson.build
+++ b/meson.build
@@ -20,24 +20,25 @@ resources = gnome.compile_resources(
   c_name: 'ahfail'
 )
 
+# Each cargo target uses its own --target-dir to avoid parallel lock contention.
 cargo_target = custom_target(
   'ahfail-cargo-build',
   input: ['crates/ahfail-gtklock/src/lib.rs', 'Cargo.toml'],
   output: ['libahfail_module.a'],
   command: [
-    'sh', '-c', 'cargo build --release -p ahfail-gtklock --target-dir "@OUTDIR@/target" && cp "@OUTDIR@/target/release/libahfail_module.a" "@OUTPUT@"'
+    'sh', '-c', 'cargo build --release -p ahfail-gtklock --target-dir "@OUTDIR@/target-gtklock" && cp "@OUTDIR@/target-gtklock/release/libahfail_module.a" "@OUTPUT@"'
   ],
   build_by_default: true
 )
 
-# PAM module (.so with C ABI — no resources needed, Cargo self-contained)
+# PAM module (.so with C ABI — no GResources needed, Cargo self-contained via build.rs)
 pam_cargo = custom_target(
   'ahfail-pam-cargo-build',
   input: ['crates/ahfail-pam/src/lib.rs', 'Cargo.toml'],
   output: ['libahfail_pam.so'],
   command: [
     'sh', '-c',
-    'cargo build --release -p ahfail-pam --target-dir "@OUTDIR@/target" && cp "@OUTDIR@/target/release/libahfail_pam.so" "@OUTPUT@"'
+    'cargo build --release -p ahfail-pam --target-dir "@OUTDIR@/target-pam" && cp "@OUTDIR@/target-pam/release/libahfail_pam.so" "@OUTPUT@"'
   ],
   build_by_default: true,
   install: true,
@@ -45,14 +46,14 @@ pam_cargo = custom_target(
   install_mode: 'rwxr-xr-x'
 )
 
-# Display binary (embeds GResources via its own build.rs)
+# Display binary (embeds GResources via its own build.rs using glib-compile-resources)
 display_cargo = custom_target(
   'ahfail-display-cargo-build',
   input: ['crates/ahfail-display/src/main.rs', 'Cargo.toml'],
   output: ['ahfail-display'],
   command: [
     'sh', '-c',
-    'cargo build --release -p ahfail-display --target-dir "@OUTDIR@/target" && cp "@OUTDIR@/target/release/ahfail-display" "@OUTPUT@"'
+    'cargo build --release -p ahfail-display --target-dir "@OUTDIR@/target-display" && cp "@OUTDIR@/target-display/release/ahfail-display" "@OUTPUT@"'
   ],
   build_by_default: true,
   install: true,
@@ -81,3 +82,12 @@ smoke = executable(
 )
 
 test('module symbols', smoke)
+
+# PAM module smoke test: dlopen libahfail_pam.so and verify pam_sm_authenticate is exported.
+pam_smoke = executable(
+  'pam_smoke_test',
+  'tests/pam_smoke_test.c',
+  dependencies: [cc.find_library('dl', required: true)]
+)
+
+test('pam symbols', pam_smoke, args: [pam_cargo[0]])
diff --git a/tests/pam_smoke_test.c b/tests/pam_smoke_test.c
new file mode 100644
index 0000000..82c1ec4
--- /dev/null
+++ b/tests/pam_smoke_test.c
@@ -0,0 +1,18 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+int main(int argc, char *argv[]) {
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s <libahfail_pam.so>\n", argv[0]);
+        return 1;
+    }
+    void *lib = dlopen(argv[1], RTLD_NOW);
+    if (!lib) { fprintf(stderr, "dlopen: %s\n", dlerror()); return 1; }
+    if (!dlsym(lib, "pam_sm_authenticate")) {
+        fprintf(stderr, "pam_sm_authenticate not found\n");
+        dlclose(lib);
+        return 1;
+    }
+    dlclose(lib);
+    return 0;
+}