fix(prof): Add running PHP language tests for profiler and fix discovered bugs

.github/workflows/prof_asan.yml

@@ -127,6 +127,25 @@ jobs:
           cargo build --profile profiler-release
           cp -v "$CARGO_TARGET_DIR/profiler-release/libdatadog_php_profiling.so" "$(php-config --extension-dir)/datadog-profiling.so"
 
+      # TODO(parallel): the php-8.5_bookworm-8 image ships parallel 1.2.13, which
+      # has a bug that intermittently trips UBSAN. Install the fixed 1.2.14 over
+      # it (ZTS-only; parallel requires ZTS). Remove this step once the CI images
+      # are rebuilt with parallel >= 1.2.14.
+      - name: Install fixed parallel 1.2.14 (ZTS only, temporary until images rebuilt)
+        if: matrix.php-build == 'zts'
+        run: |
+          set -eux
+          switch-php zts
+          scan_dir="$(php -r 'echo PHP_CONFIG_FILE_SCAN_DIR;')"
+          # pecl refuses to reinstall while the extension is loaded, so move its
+          # ini aside during the build, then restore it so the test run loads the
+          # freshly installed parallel.so. Use the direct package URL because the
+          # channel REST cache in the image can lag behind new releases.
+          mv "$scan_dir/parallel.ini" /tmp/parallel.ini.disabled
+          yes '' | pecl install -f https://pecl.php.net/get/parallel-1.2.14.tgz
+          mv /tmp/parallel.ini.disabled "$scan_dir/parallel.ini"
+          php --ri parallel | grep -i version
+
       - name: Run phpt tests
         run: |
           set -eux

.gitlab/generate-profiler.php

@@ -13,6 +13,16 @@
 }
 ?>
 
+# PHP 8.5 has a known tailcall VM crash; re-enable once PHP 8.5.8 is available.
+.php_language_profiler_targets: &php_language_profiler_targets
+<?php
+foreach ($profiler_minor_major_targets as $version) {
+    if (version_compare($version, "8.5", "<")) {
+        echo "  - \"{$version}\"\n";
+    }
+}
+?>
+
 "profiling tests":
   stage: test
   tags: [ "arch:${ARCH}" ]
@@ -44,6 +54,8 @@
   script:
     - if [ -d '/opt/rh/devtoolset-7' ]; then set +eo pipefail; source scl_source enable devtoolset-7; set -eo pipefail; fi
     - if [ -d '/opt/rh/devtoolset-7' ] && [ "$(uname -m)" = "aarch64" ]; then export BINDGEN_EXTRA_CLANG_ARGS="-I$(clang --print-resource-dir)/include"; fi
+    - if [ -f /sbin/apk ] && [ $(uname -m) = "aarch64" ]; then ln -sf ../lib/llvm17/bin/clang /usr/bin/clang; fi
+    - export DD_PROFILING_OUTPUT_PPROF=/tmp/
 
     - cd profiling
     - 'echo "nproc: $(nproc)"'
@@ -86,8 +98,13 @@
   image: registry.ddbuild.io/images/mirror/datadog/dd-trace-ci:php-${PHP_MAJOR_MINOR}_bookworm-8
   variables:
     KUBERNETES_CPU_REQUEST: 5
+    KUBERNETES_CPU_LIMIT: 5
     KUBERNETES_MEMORY_REQUEST: 3Gi
-    KUBERNETES_MEMORY_LIMIT: 4Gi
+    KUBERNETES_MEMORY_LIMIT: 3Gi
+    KUBERNETES_HELPER_CPU_REQUEST: 1
+    KUBERNETES_HELPER_CPU_LIMIT: 1
+    KUBERNETES_HELPER_MEMORY_REQUEST: 2Gi
+    KUBERNETES_HELPER_MEMORY_LIMIT: 2Gi
     # CARGO_TARGET_DIR: /mnt/ramdisk/cargo # ramdisk??
     libdir: /tmp/datadog-profiling
   parallel:
@@ -105,11 +122,56 @@
   image: registry.ddbuild.io/images/mirror/datadog/dd-trace-ci:php-8.5_bookworm-8
   variables:
     KUBERNETES_CPU_REQUEST: 5
+    KUBERNETES_CPU_LIMIT: 5
     KUBERNETES_MEMORY_REQUEST: 3Gi
-    KUBERNETES_MEMORY_LIMIT: 4Gi
+    KUBERNETES_MEMORY_LIMIT: 3Gi
+    KUBERNETES_HELPER_CPU_REQUEST: 1
+    KUBERNETES_HELPER_CPU_LIMIT: 1
+    KUBERNETES_HELPER_MEMORY_REQUEST: 2Gi
+    KUBERNETES_HELPER_MEMORY_LIMIT: 2Gi
     # CARGO_TARGET_DIR: /mnt/ramdisk/cargo # ramdisk??
     libdir: /tmp/datadog-profiling
   script:
     - switch-php nts # not compatible with debug
     - cd profiling
     - cargo test --all-features
+
+"PHP language tests":
+  stage: test
+  tags: [ "arch:${ARCH}" ]
+  image: registry.ddbuild.io/images/mirror/datadog/dd-trace-ci:php-${PHP_MAJOR_MINOR}_bookworm-8
+  variables:
+    KUBERNETES_CPU_REQUEST: 5
+    KUBERNETES_CPU_LIMIT: 5
+    KUBERNETES_MEMORY_REQUEST: 3Gi
+    KUBERNETES_MEMORY_LIMIT: 3Gi
+    KUBERNETES_HELPER_CPU_REQUEST: 1
+    KUBERNETES_HELPER_CPU_LIMIT: 1
+    KUBERNETES_HELPER_MEMORY_REQUEST: 2Gi
+    KUBERNETES_HELPER_MEMORY_LIMIT: 2Gi
+    CARGO_TARGET_DIR: /tmp/cargo
+    libdir: /tmp/datadog-profiling
+    SKIP_ONLINE_TESTS: "1"
+    REPORT_EXIT_STATUS: "1"
+    DD_PROFILING_OUTPUT_PPROF: /tmp/
+    XFAIL_LIST: dockerfiles/ci/xfail_tests/${PHP_MAJOR_MINOR}.list
+  parallel:
+    matrix:
+      - PHP_MAJOR_MINOR: *php_language_profiler_targets
+        ARCH: amd64
+        FLAVOUR: [nts, zts]
+  script:
+    - unset DD_SERVICE; unset DD_ENV
+    - command -v switch-php && switch-php "${FLAVOUR}"
+    - cd profiling
+    - cargo build --profile profiler-release
+    - cd ..
+    - echo "extension=/tmp/cargo/profiler-release/libdatadog_php_profiling.so" > /opt/php/${FLAVOUR}/conf.d/profiling.ini
+    - php -v
+    # Fail loudly if the profiler did not load: otherwise the language tests
+    # would run profiler-less and pass, giving a false green.
+    - php -m | grep -qx 'datadog-profiling' || { echo 'ERROR: datadog-profiling extension is not loaded'; exit 1; }
+    - cat "${XFAIL_LIST}" profiling/tests/php-language-xfail.list > /tmp/profiler-php-language-xfail.list
+    - if php -r 'exit(PHP_VERSION_ID < 80400 ? 0 : 1);'; then cat profiling/tests/php-language-xfail-pre84.list >> /tmp/profiler-php-language-xfail.list; fi
+    - export XFAIL_LIST=/tmp/profiler-php-language-xfail.list
+    - .gitlab/run_php_language_tests.sh

.gitlab/run_php_language_tests.sh

@@ -4,8 +4,18 @@ set -eo pipefail
 # Helper to parse version strings for comparison
 function version { echo "$@" | awk -F. '{ printf("%d%03d%03d%03d\n", $1,$2,$3,$4); }'; }
 
-sudo rm -f /opt/php/debug/conf.d/memcached.ini
-sudo rm -f /opt/php/debug/conf.d/rdkafka.ini
+# Remove extensions whose mere presence pollutes test output or output
+# ordering:
+#  - rdkafka emits CONFWARN lines, breaking Zend/tests/instantiate_all_classes.phpt
+#  - parallel (ZTS-only) defers 'PHP Startup' diagnostics until after the
+#    script's first output, breaking ~56 deprecation/warning-ordering tests
+# Derive the scan dir from the active PHP so this works for every build
+# variant (debug for the tracer job, nts/zts for the profiler job) instead
+# of hardcoding the debug path.
+scan_dir="$(php -r 'echo PHP_CONFIG_FILE_SCAN_DIR;')"
+sudo rm -f "${scan_dir}/memcached.ini"
+sudo rm -f "${scan_dir}/rdkafka.ini"
+sudo rm -f "${scan_dir}/parallel.ini"
 if [[ ! "${XFAIL_LIST:-none}" == "none" ]]; then
   cp "${XFAIL_LIST}" /usr/local/src/php/xfail_tests.list
   (

profiling/src/lib.rs

@@ -247,8 +247,10 @@ extern "C" fn minit(_type: c_int, module_number: c_int) -> ZendResult {
         use std::sync::Mutex;
 
         let fd = loop {
-            // SAFETY:
-            let result = unsafe { libc::dup(libc::STDERR_FILENO) };
+            // F_DUPFD_CLOEXEC (not plain dup) so the duplicate is not inherited
+            // by child processes spawned via proc_open()/exec(). See logging.rs.
+            // SAFETY: just a libc call.
+            let result = unsafe { libc::fcntl(libc::STDERR_FILENO, libc::F_DUPFD_CLOEXEC, 0) };
             if result != -1 {
                 break result;
             } else {

profiling/src/logging.rs

@@ -12,7 +12,11 @@ pub fn log_init(level_filter: LevelFilter) {
      */
 
     // Safety: this is safe, it's just "unsafe" because it's a call into C.
-    let fd = unsafe { libc::dup(libc::STDERR_FILENO) };
+    // F_DUPFD_CLOEXEC (not plain dup) so the duplicate is not inherited by
+    // child processes spawned via proc_open()/exec(). A leaked stderr dup
+    // keeps pipes open and hangs. Observable in `run-tests.php` in PHP
+    // (e.g. ext/curl/tests/curl_setopt_ssl.phpt spawning `openssl s_server`).
+    let fd = unsafe { libc::fcntl(libc::STDERR_FILENO, libc::F_DUPFD_CLOEXEC, 0) };
     if fd != -1 {
         // Safety: the fd is a valid and open file descriptor, and the File has sole ownership.
         let target = Box::new(unsafe { File::from_raw_fd(fd) });

profiling/src/profiling/thread_utils.rs

@@ -20,25 +20,38 @@ where
     let result = std::thread::Builder::new()
         .name(name.to_string())
         .spawn(move || {
-            /* Thread must not handle signals intended for PHP threads.
-             * See Zend/zend_signal.c for which signals it registers.
+            /* This helper thread has no valid PHP/TSRM context, so it must not
+             * run any PHP signal handler. The Zend Engine registers a fixed set
+             * of signals (see Zend/zend_signal.c), but a PHP script can install
+             * a handler for *any* signal via pcntl_signal() (e.g. SIGCHLD with
+             * pcntl_async_signals(true)). If such a signal is delivered to this
+             * thread, pcntl_signal_handler() dereferences PCNTL_G(spares) with
+             * no thread context and segfaults
+             * (see ext/pcntl/tests/waiting_on_sigchild_pcntl_wait.phpt).
+             *
+             * So block every signal here; async signals are then delivered to a
+             * PHP thread instead. The synchronous fault signals are left
+             * unblocked so a genuine fault on this thread is still reported
+             * (e.g. by the crashtracker) rather than masked.
              */
             unsafe {
                 let mut sigset_mem = MaybeUninit::uninit();
                 let sigset = sigset_mem.as_mut_ptr();
-                libc::sigemptyset(sigset);
-
-                const SIGNALS: [libc::c_int; 6] = [
-                    libc::SIGPROF, // todo: SIGALRM on __CYGWIN__/__PHASE__
-                    libc::SIGHUP,
-                    libc::SIGINT,
-                    libc::SIGTERM,
-                    libc::SIGUSR1,
-                    libc::SIGUSR2,
+                libc::sigfillset(sigset);
+
+                // Hardware/synchronous fault signals: keep them deliverable to
+                // this thread.
+                const KEEP_UNBLOCKED: [libc::c_int; 6] = [
+                    libc::SIGSEGV,
+                    libc::SIGBUS,
+                    libc::SIGFPE,
+                    libc::SIGILL,
+                    libc::SIGABRT,
+                    libc::SIGTRAP,
                 ];
 
-                for signal in SIGNALS {
-                    libc::sigaddset(sigset, signal);
+                for signal in KEEP_UNBLOCKED {
+                    libc::sigdelset(sigset, signal);
                 }
                 libc::pthread_sigmask(libc::SIG_BLOCK, sigset, std::ptr::null_mut());
             }

profiling/src/timeline.rs

@@ -245,12 +245,23 @@ unsafe extern "C" fn ddog_php_prof_zend_error_observer(
         return;
     }
 
+    // The engine passes a NULL file for fatal errors with no active file
+    // location, e.g. an uncaught exception reported via zend_exception_error
+    // (`zend_error_va(..., file=NULL, ...)`). CStr::from_ptr(NULL) would
+    // strlen(NULL) and segfault, so guard against it. See
+    // Zend/tests/bug50005.phpt and Zend/tests/bug64821.3.phpt.
     #[cfg(zend_error_observer_80)]
-    let filename_str = unsafe { core::ffi::CStr::from_ptr(file) };
+    let filename = if file.is_null() {
+        String::new()
+    } else {
+        unsafe { core::ffi::CStr::from_ptr(file) }
+            .to_string_lossy()
+            .into_owned()
+    };
     #[cfg(not(zend_error_observer_80))]
-    let filename_str = unsafe { zai_str_from_zstr(file.as_mut()) };
-
-    let filename = filename_str.to_string_lossy().into_owned();
+    let filename = unsafe { zai_str_from_zstr(file.as_mut()) }
+        .to_string_lossy()
+        .into_owned();
 
     let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
     if let Some(profiler) = Profiler::get() {

profiling/tests/README.md

@@ -0,0 +1,43 @@
+# PHP language test xfail lists
+
+The profiler's "PHP language tests" CI job runs the upstream PHP test suite
+with the profiling extension loaded, for every supported PHP version and for
+both the `nts` and `zts` builds. These lists exclude tests that cannot pass in
+that environment for reasons unrelated to profiler correctness.
+
+`.gitlab/run_php_language_tests.sh` **deletes** every `.phpt` named in
+`XFAIL_LIST` before running, so listing a test means "do not run" it.
+
+| File | Applies to |
+|------|------------|
+| `php-language-xfail.list` | all profiler runs (`nts` + `zts`, all versions) |
+| `php-language-xfail-pre84.list` | PHP < 8.4 (appended by the job via a version check) |
+
+## `php-language-xfail.list` (all versions)
+
+Fail with the profiler loaded regardless of version/flavour:
+
+- `ext/ffi/tests/list.phpt` — aborts (`free(): invalid size`); allocation
+  profiler conflicts with the test's FFI memory management.
+- `Zend/tests/concat_003.phpt` — perf-sensitive (2 s budget); allocation
+  profiling overhead can exceed it on CI runners.
+- `ext/session/tests/bug60634.phpt` (also under `user_session_module/` on some
+  versions; both paths are listed) — `die()` inside a session save handler.
+  Fails intermittently in the parallel run with "Cannot call session save
+  handler in a recursive manner". Not a profiler issue: it passes in isolation
+  with the profiler enabled; it's a concurrency/session-save-path collision in
+  the 64-worker run. Listed because it is flaky under parallelism.
+
+## `php-language-xfail-pre84.list` (PHP < 8.4)
+
+`php-language-xfail-pre84.list` contains opcache optimizer-output tests that
+fail only with the profiler on PHP ≤ 8.3. On PHP < 8.4 the profiler overrides
+`zend_execute_internal` (to handle VM interrupts while an internal function is
+on the stack); on 8.4+ that hook is not installed (frameless calls), so these
+pass. Internal calls therefore compile to `DO_FCALL` instead of `DO_ICALL`,
+changing the optimized opcodes.
+
+- `opt/prop_types.phpt`, `opt/gh11170.phpt`, `opt/nullsafe_002.phpt` — cosmetic
+  opcode-dump differences (`DO_ICALL` → `DO_FCALL`).
+- `bug66251.phpt` — same `< 8.4` condition: with the execute hook installed,
+  opcache folds a same-file runtime constant that should stay dynamic.

profiling/tests/php-language-xfail-pre84.list

@@ -0,0 +1,4 @@
+ext/opcache/tests/opt/prop_types.phpt
+ext/opcache/tests/opt/gh11170.phpt
+ext/opcache/tests/opt/nullsafe_002.phpt
+ext/opcache/tests/bug66251.phpt

profiling/tests/php-language-xfail.list

@@ -0,0 +1,4 @@
+Zend/tests/concat_003.phpt
+ext/ffi/tests/list.phpt
+ext/session/tests/bug60634.phpt
+ext/session/tests/user_session_module/bug60634.phpt

profiling/tests/phpt/pcntl_async_signal_helper_thread.phpt

@@ -0,0 +1,77 @@
+--TEST--
+[profiling] async PHP signal handlers must not run on profiler helper threads
+--DESCRIPTION--
+Regression test for a crash when a PHP script installs an async signal handler
+(pcntl_async_signals(true) + pcntl_signal()) for a signal the Zend Engine does
+not itself register, e.g. SIGCHLD.
+
+The profiler's helper threads (`ddprof_time`, `ddprof_upload`) only masked the
+fixed set of signals the Zend Engine uses, so the kernel could deliver SIGCHLD
+to one of them. pcntl's handler then ran on a thread with no valid PHP/TSRM
+context and dereferenced the thread-local PCNTL_G, segfaulting. The fix is to
+block every (non-fault) signal on the helper threads so async signals are
+delivered to a PHP thread.
+
+Only crashes on ZTS, where PCNTL_G is thread-local. Observed on PHP 8.4 ZTS,
+reproduced by ext/pcntl/tests/waiting_on_sigchild_pcntl_wait.phpt:
+
+    Thread 2 "ddprof_time" received signal SIGSEGV, Segmentation fault.
+    #0  pcntl_signal_handler (signo=17, ...) at ext/pcntl/pcntl.c:1289
+    1289        struct php_pcntl_pending_signal *psig = PCNTL_G(spares);
+    #1  <signal handler called>
+    #2  syscall ()
+    #3  std::sys::pal::unix::futex::futex_wait ()
+    #4  std::sys::sync::thread_parking::futex::Parker::park_timeout ()
+    ...
+    #15 run () at profiling/src/profiling/uploader.rs:157
+    #16 {closure#3} () at profiling/src/profiling/mod.rs:898
+    #17 ... at profiling/src/profiling/thread_utils.rs:45
+--SKIPIF--
+<?php
+foreach (['datadog-profiling', 'pcntl'] as $extension)
+    if (!extension_loaded($extension))
+        echo "skip: test requires {$extension}\n";
+if (!ZEND_THREAD_SAFE)
+    echo "skip: ZTS only (the crash is a thread-local PCNTL_G access from a helper thread)\n";
+if (PHP_OS_FAMILY !== 'Linux')
+    echo "skip: Linux only\n";
+if (getenv('SKIP_ASAN'))
+    die('skip: the profiler leaks on purpose in child of a fork');
+?>
+--ENV--
+DD_PROFILING_ENABLED=yes
+DD_PROFILING_LOG_LEVEL=off
+--FILE--
+<?php
+
+pcntl_async_signals(true);
+
+$processes = [];
+pcntl_signal(SIGCHLD, function () use (&$processes) {
+    while (($pid = pcntl_wait($status, WUNTRACED | WNOHANG)) > 0) {
+        unset($processes[$pid]);
+    }
+});
+
+// Spawn bursts of short-lived children. They exit at roughly the same time, so
+// a burst of SIGCHLD arrives while the main thread is idle in usleep(). If the
+// profiler's helper threads do not block SIGCHLD the kernel may deliver it to
+// one of them, where pcntl's handler runs without a PHP/TSRM context and
+// crashes. Several rounds widen the (timing-dependent) race window.
+for ($round = 0; $round < 4; $round++) {
+    for ($i = 0; $i < 8; $i++) {
+        $proc = proc_open('sleep 0.3', [], $pipes);
+        if ($proc !== false) {
+            $processes[proc_get_status($proc)['pid']] = $proc;
+        }
+    }
+    $iters = 50;
+    while (!empty($processes) && $iters-- > 0) {
+        usleep(100000);
+    }
+}
+
+echo empty($processes) ? "OK\n" : "leftover children\n";
+?>
+--EXPECT--
+OK