Avoid lock poisoning by using parking_lot

parking_lot provides synchronization primitives which aren't
poisoned on panic. This makes it easier to determine which tests
are failing, as a test failure no longer causes all subsequent tests
using that mutex to fail.

13 files changed, 59 insertions, 63 deletions

diff --git a/Cargo.toml b/Cargo.toml
index fc960255..f5c7a565 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -38,6 +38,7 @@ cc = "1"
 [dev-dependencies]
 assert-impl = "0.1"
 lazy_static = "1.2"
+parking_lot = "0.11.2"
 rand = "0.8"
 tempfile = "3.2.0"
 semver = "1.0.0"
diff --git a/test/sys/test_aio.rs b/test/sys/test_aio.rs
index b4eb3129..80cd053f 100644
--- a/test/sys/test_aio.rs
+++ b/test/sys/test_aio.rs
@@ -406,7 +406,7 @@ extern fn sigfunc(_: c_int) {
 #[test]
 #[cfg_attr(any(all(target_env = "musl", target_arch = "x86_64"), target_arch = "mips", target_arch = "mips64"), ignore)]
 fn test_write_sigev_signal() {
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
     let sa = SigAction::new(SigHandler::Handler(sigfunc),
                             SaFlags::SA_RESETHAND,
                             SigSet::empty());
@@ -544,7 +544,7 @@ fn test_liocb_listio_nowait() {
 #[cfg(not(any(target_os = "ios", target_os = "macos")))]
 #[cfg_attr(any(target_arch = "mips", target_arch = "mips64", target_env = "musl"), ignore)]
 fn test_liocb_listio_signal() {
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
     const INITIAL: &[u8] = b"abcdef123456";
     const WBUF: &[u8] = b"CDEF";
     let mut rbuf = vec![0; 4];
diff --git a/test/sys/test_ptrace.rs b/test/sys/test_ptrace.rs
index 1c72e7c2..83fff9a5 100644
--- a/test/sys/test_ptrace.rs
+++ b/test/sys/test_ptrace.rs
@@ -69,7 +69,7 @@ fn test_ptrace_cont() {
 
     require_capability!("test_ptrace_cont", CAP_SYS_PTRACE);
 
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     // FIXME: qemu-user doesn't implement ptrace on all architectures
     // and retunrs ENOSYS in this case.
@@ -127,7 +127,7 @@ fn test_ptrace_interrupt() {
 
     require_capability!("test_ptrace_interrupt", CAP_SYS_PTRACE);
 
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     match unsafe{fork()}.expect("Error: Fork Failed") {
         Child => {
@@ -173,7 +173,7 @@ fn test_ptrace_syscall() {
 
     require_capability!("test_ptrace_syscall", CAP_SYS_PTRACE);
 
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     match unsafe{fork()}.expect("Error: Fork Failed") {
         Child => {
diff --git a/test/sys/test_select.rs b/test/sys/test_select.rs
index db079456..2f7396b1 100644
--- a/test/sys/test_select.rs
+++ b/test/sys/test_select.rs
@@ -5,9 +5,7 @@ use nix::sys::time::{TimeSpec, TimeValLike};
 
 #[test]
 pub fn test_pselect() {
-    let _mtx = crate::SIGNAL_MTX
-        .lock()
-        .expect("Mutex got poisoned by another test");
+    let _mtx = crate::SIGNAL_MTX.lock();
 
     let (r1, w1) = pipe().unwrap();
     write(w1, b"hi!").unwrap();
diff --git a/test/sys/test_signal.rs b/test/sys/test_signal.rs
index 1b89af57..fdd2568d 100644
--- a/test/sys/test_signal.rs
+++ b/test/sys/test_signal.rs
@@ -19,7 +19,7 @@ fn test_killpg_none() {
 
 #[test]
 fn test_old_sigaction_flags() {
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
 
     extern "C" fn handler(_: ::libc::c_int) {}
     let act = SigAction::new(
@@ -41,7 +41,7 @@ fn test_sigprocmask_noop() {
 
 #[test]
 fn test_sigprocmask() {
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
 
     // This needs to be a signal that rust doesn't use in the test harness.
     const SIGNAL: Signal = Signal::SIGCHLD;
@@ -89,7 +89,7 @@ extern fn test_sigaction_action(_: libc::c_int, _: *mut libc::siginfo_t, _: *mut
 #[test]
 #[cfg(not(target_os = "redox"))]
 fn test_signal_sigaction() {
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
 
     let action_handler = SigHandler::SigAction(test_sigaction_action);
     assert_eq!(unsafe { signal(Signal::SIGINT, action_handler) }.unwrap_err(), Errno::ENOTSUP);
@@ -97,7 +97,7 @@ fn test_signal_sigaction() {
 
 #[test]
 fn test_signal() {
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
 
     unsafe { signal(Signal::SIGINT, SigHandler::SigIgn) }.unwrap();
     raise(Signal::SIGINT).unwrap();
diff --git a/test/sys/test_signalfd.rs b/test/sys/test_signalfd.rs
index af04c222..b6f748b4 100644
--- a/test/sys/test_signalfd.rs
+++ b/test/sys/test_signalfd.rs
@@ -6,7 +6,7 @@ fn test_signalfd() {
     use nix::sys::signal::{self, raise, Signal, SigSet};
 
     // Grab the mutex for altering signals so we don't interfere with other tests.
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
 
     // Block the SIGUSR1 signal from automatic processing for this thread
     let mut mask = SigSet::empty();
diff --git a/test/sys/test_termios.rs b/test/sys/test_termios.rs
index 63d6a51f..4a861543 100644
--- a/test/sys/test_termios.rs
+++ b/test/sys/test_termios.rs
@@ -19,7 +19,7 @@ fn write_all(f: RawFd, buf: &[u8]) {
 #[test]
 fn test_tcgetattr_pty() {
     // openpty uses ptname(3) internally
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     let pty = openpty(None, None).expect("openpty failed");
     assert!(termios::tcgetattr(pty.slave).is_ok());
@@ -46,7 +46,7 @@ fn test_tcgetattr_ebadf() {
 #[test]
 fn test_output_flags() {
     // openpty uses ptname(3) internally
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     // Open one pty to get attributes for the second one
     let mut termios = {
@@ -88,7 +88,7 @@ fn test_output_flags() {
 #[test]
 fn test_local_flags() {
     // openpty uses ptname(3) internally
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     // Open one pty to get attributes for the second one
     let mut termios = {
diff --git a/test/sys/test_uio.rs b/test/sys/test_uio.rs
index 8f8ba5e4..408537c8 100644
--- a/test/sys/test_uio.rs
+++ b/test/sys/test_uio.rs
@@ -214,7 +214,7 @@ fn test_process_vm_readv() {
     use crate::*;
 
     require_capability!("test_process_vm_readv", CAP_SYS_PTRACE);
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     // Pre-allocate memory in the child, since allocation isn't safe
     // post-fork (~= async-signal-safe)
diff --git a/test/sys/test_wait.rs b/test/sys/test_wait.rs
index 4a5b9661..afe4f42b 100644
--- a/test/sys/test_wait.rs
+++ b/test/sys/test_wait.rs
@@ -8,7 +8,7 @@ use libc::_exit;
 #[test]
 #[cfg(not(target_os = "redox"))]
 fn test_wait_signal() {
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     // Safe: The child only calls `pause` and/or `_exit`, which are async-signal-safe.
     match unsafe{fork()}.expect("Error: Fork Failed") {
@@ -25,7 +25,7 @@ fn test_wait_signal() {
 
 #[test]
 fn test_wait_exit() {
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     // Safe: Child only calls `_exit`, which is async-signal-safe.
     match unsafe{fork()}.expect("Error: Fork Failed") {
@@ -46,7 +46,7 @@ fn test_waitstatus_from_raw() {
 
 #[test]
 fn test_waitstatus_pid() {
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     match unsafe{fork()}.unwrap() {
         Child => unsafe { _exit(0) },
@@ -97,7 +97,7 @@ mod ptrace {
     #[test]
     fn test_wait_ptrace() {
         require_capability!("test_wait_ptrace", CAP_SYS_PTRACE);
-        let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+        let _m = crate::FORK_MTX.lock();
 
         match unsafe{fork()}.expect("Error: Fork Failed") {
             Child => ptrace_child(),
diff --git a/test/test.rs b/test/test.rs
index b882d174..aade937a 100644
--- a/test/test.rs
+++ b/test/test.rs
@@ -43,7 +43,7 @@ mod test_unistd;
 
 use std::os::unix::io::RawFd;
 use std::path::PathBuf;
-use std::sync::{Mutex, RwLock, RwLockWriteGuard};
+use parking_lot::{Mutex, RwLock, RwLockWriteGuard};
 use nix::unistd::{chdir, getcwd, read};
 
 
@@ -84,8 +84,7 @@ struct DirRestore<'a> {
 
 impl<'a> DirRestore<'a> {
     fn new() -> Self {
-        let guard = crate::CWD_LOCK.write()
-            .expect("Lock got poisoned by another test");
+        let guard = crate::CWD_LOCK.write();
         DirRestore{
             _g: guard,
             d: getcwd().unwrap(),
diff --git a/test/test_kmod/mod.rs b/test/test_kmod/mod.rs
index 0f7fc48e..8eef5384 100644
--- a/test/test_kmod/mod.rs
+++ b/test/test_kmod/mod.rs
@@ -5,9 +5,7 @@ use tempfile::{tempdir, TempDir};
 use crate::*;
 
 fn compile_kernel_module() -> (PathBuf, String, TempDir) {
-    let _m = crate::FORK_MTX
-        .lock()
-        .expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     let tmp_dir = tempdir().expect("unable to create temporary build directory");
 
@@ -41,8 +39,8 @@ use std::io::Read;
 #[test]
 fn test_finit_and_delete_module() {
     require_capability!("test_finit_and_delete_module", CAP_SYS_MODULE);
-    let _m0 = crate::KMOD_MTX.lock().expect("Mutex got poisoned by another test");
-    let _m1 = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m0 = crate::KMOD_MTX.lock();
+    let _m1 = crate::CWD_LOCK.read();
 
     let (kmod_path, kmod_name, _kmod_dir) = compile_kernel_module();
 
@@ -59,8 +57,8 @@ fn test_finit_and_delete_module() {
 #[test]
 fn test_finit_and_delete_module_with_params() {
     require_capability!("test_finit_and_delete_module_with_params", CAP_SYS_MODULE);
-    let _m0 = crate::KMOD_MTX.lock().expect("Mutex got poisoned by another test");
-    let _m1 = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m0 = crate::KMOD_MTX.lock();
+    let _m1 = crate::CWD_LOCK.read();
 
     let (kmod_path, kmod_name, _kmod_dir) = compile_kernel_module();
 
@@ -80,8 +78,8 @@ fn test_finit_and_delete_module_with_params() {
 #[test]
 fn test_init_and_delete_module() {
     require_capability!("test_init_and_delete_module", CAP_SYS_MODULE);
-    let _m0 = crate::KMOD_MTX.lock().expect("Mutex got poisoned by another test");
-    let _m1 = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m0 = crate::KMOD_MTX.lock();
+    let _m1 = crate::CWD_LOCK.read();
 
     let (kmod_path, kmod_name, _kmod_dir) = compile_kernel_module();
 
@@ -100,8 +98,8 @@ fn test_init_and_delete_module() {
 #[test]
 fn test_init_and_delete_module_with_params() {
     require_capability!("test_init_and_delete_module_with_params", CAP_SYS_MODULE);
-    let _m0 = crate::KMOD_MTX.lock().expect("Mutex got poisoned by another test");
-    let _m1 = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m0 = crate::KMOD_MTX.lock();
+    let _m1 = crate::CWD_LOCK.read();
 
     let (kmod_path, kmod_name, _kmod_dir) = compile_kernel_module();
 
@@ -121,8 +119,8 @@ fn test_init_and_delete_module_with_params() {
 #[test]
 fn test_finit_module_invalid() {
     require_capability!("test_finit_module_invalid", CAP_SYS_MODULE);
-    let _m0 = crate::KMOD_MTX.lock().expect("Mutex got poisoned by another test");
-    let _m1 = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m0 = crate::KMOD_MTX.lock();
+    let _m1 = crate::CWD_LOCK.read();
 
     let kmod_path = "/dev/zero";
 
@@ -135,8 +133,8 @@ fn test_finit_module_invalid() {
 #[test]
 fn test_finit_module_twice_and_delete_module() {
     require_capability!("test_finit_module_twice_and_delete_module", CAP_SYS_MODULE);
-    let _m0 = crate::KMOD_MTX.lock().expect("Mutex got poisoned by another test");
-    let _m1 = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m0 = crate::KMOD_MTX.lock();
+    let _m1 = crate::CWD_LOCK.read();
 
     let (kmod_path, kmod_name, _kmod_dir) = compile_kernel_module();
 
@@ -157,8 +155,8 @@ fn test_finit_module_twice_and_delete_module() {
 #[test]
 fn test_delete_module_not_loaded() {
     require_capability!("test_delete_module_not_loaded", CAP_SYS_MODULE);
-    let _m0 = crate::KMOD_MTX.lock().expect("Mutex got poisoned by another test");
-    let _m1 = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m0 = crate::KMOD_MTX.lock();
+    let _m1 = crate::CWD_LOCK.read();
 
     let result = delete_module(&CString::new("hello").unwrap(), DeleteModuleFlags::empty());
 
diff --git a/test/test_pty.rs b/test/test_pty.rs
index 57874de3..71932f2d 100644
--- a/test/test_pty.rs
+++ b/test/test_pty.rs
@@ -29,7 +29,7 @@ fn test_explicit_close() {
 #[test]
 #[cfg(any(target_os = "android", target_os = "linux"))]
 fn test_ptsname_equivalence() {
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     // Open a new PTTY master
     let master_fd = posix_openpt(OFlag::O_RDWR).unwrap();
@@ -46,7 +46,7 @@ fn test_ptsname_equivalence() {
 #[test]
 #[cfg(any(target_os = "android", target_os = "linux"))]
 fn test_ptsname_copy() {
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     // Open a new PTTY master
     let master_fd = posix_openpt(OFlag::O_RDWR).unwrap();
@@ -80,7 +80,7 @@ fn test_ptsname_r_copy() {
 #[test]
 #[cfg(any(target_os = "android", target_os = "linux"))]
 fn test_ptsname_unique() {
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     // Open a new PTTY master
     let master1_fd = posix_openpt(OFlag::O_RDWR).unwrap();
@@ -98,7 +98,7 @@ fn test_ptsname_unique() {
 
 /// Common setup for testing PTTY pairs
 fn open_ptty_pair() -> (PtyMaster, File) {
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     // Open a new PTTY master
     let master = posix_openpt(OFlag::O_RDWR).expect("posix_openpt failed");
@@ -114,7 +114,7 @@ fn open_ptty_pair() -> (PtyMaster, File) {
     let slave_fd = open(Path::new(&slave_name), OFlag::O_RDWR, stat::Mode::empty()).unwrap();
 
     #[cfg(target_os = "illumos")]
-    // TODO: rewrite using ioctl! 
+    // TODO: rewrite using ioctl!
     #[allow(clippy::comparison_chain)]
     {
         use libc::{ioctl, I_FIND, I_PUSH};
@@ -187,7 +187,7 @@ fn test_write_ptty_pair() {
 #[test]
 fn test_openpty() {
     // openpty uses ptname(3) internally
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     let pty = openpty(None, None).unwrap();
     assert!(pty.master > 0);
@@ -222,7 +222,7 @@ fn test_openpty() {
 #[test]
 fn test_openpty_with_termios() {
     // openpty uses ptname(3) internally
-    let _m = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::PTSNAME_MTX.lock();
 
     // Open one pty to get attributes for the second one
     let mut termios = {
@@ -273,9 +273,9 @@ fn test_forkpty() {
     use nix::sys::signal::*;
     use nix::sys::wait::wait;
     // forkpty calls openpty which uses ptname(3) internally.
-    let _m0 = crate::PTSNAME_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m0 = crate::PTSNAME_MTX.lock();
     // forkpty spawns a child process
-    let _m1 = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m1 = crate::FORK_MTX.lock();
 
     let string = "naninani\n";
     let echoed_string = "naninani\r\n";
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 3a3d49dd..3a1f9f10 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -28,7 +28,7 @@ use crate::*;
 #[test]
 #[cfg(not(any(target_os = "netbsd")))]
 fn test_fork_and_waitpid() {
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     // Safe: Child only calls `_exit`, which is signal-safe
     match unsafe{fork()}.expect("Error: Fork Failed") {
@@ -56,7 +56,7 @@ fn test_fork_and_waitpid() {
 #[test]
 fn test_wait() {
     // Grab FORK_MTX so wait doesn't reap a different test's child process
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
 
     // Safe: Child only calls `_exit`, which is signal-safe
     match unsafe{fork()}.expect("Error: Fork Failed") {
@@ -116,7 +116,7 @@ fn test_mkfifo_directory() {
     target_os = "macos", target_os = "ios",
     target_os = "android", target_os = "redox")))]
 fn test_mkfifoat_none() {
-    let _m = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m = crate::CWD_LOCK.read();
 
     let tempdir = tempdir().unwrap();
     let mkfifoat_fifo = tempdir.path().join("mkfifoat_fifo");
@@ -151,7 +151,7 @@ fn test_mkfifoat() {
     target_os = "macos", target_os = "ios",
     target_os = "android", target_os = "redox")))]
 fn test_mkfifoat_directory_none() {
-    let _m = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m = crate::CWD_LOCK.read();
 
     // mkfifoat should fail if a directory is given
     assert!(!mkfifoat(None, &env::temp_dir(), Mode::S_IRUSR).is_ok());
@@ -206,7 +206,7 @@ fn test_setgroups() {
     // Skip this test when not run as root as `setgroups()` requires root.
     skip_if_not_root!("test_setgroups");
 
-    let _m = crate::GROUPS_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::GROUPS_MTX.lock();
 
     // Save the existing groups
     let old_groups = getgroups().unwrap();
@@ -234,7 +234,7 @@ fn test_initgroups() {
     // require root.
     skip_if_not_root!("test_initgroups");
 
-    let _m = crate::GROUPS_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::GROUPS_MTX.lock();
 
     // Save the existing groups
     let old_groups = getgroups().unwrap();
@@ -304,7 +304,7 @@ macro_rules! execve_test_factory(
             skip_if_seccomp!($test_name);
         }
 
-        let m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+        let m = crate::FORK_MTX.lock();
         // The `exec`d process will write to `writer`, and we'll read that
         // data from `reader`.
         let (reader, writer) = pipe().unwrap();
@@ -575,7 +575,7 @@ fn test_acct() {
     use std::process::Command;
     use std::{thread, time};
 
-    let _m = crate::FORK_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::FORK_MTX.lock();
     require_acct!();
 
     let file = NamedTempFile::new().unwrap();
@@ -735,7 +735,7 @@ fn test_alarm() {
     };
 
     // Maybe other tests that fork interfere with this one?
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
 
     let handler = SigHandler::Handler(alarm_signal_handler);
     let signal_action = SigAction::new(handler, SaFlags::SA_RESTART, SigSet::empty());
@@ -773,7 +773,7 @@ fn test_alarm() {
 #[test]
 #[cfg(not(target_os = "redox"))]
 fn test_canceling_alarm() {
-    let _m = crate::SIGNAL_MTX.lock().expect("Mutex got poisoned by another test");
+    let _m = crate::SIGNAL_MTX.lock();
 
     assert_eq!(alarm::cancel(), None);
 
@@ -784,7 +784,7 @@ fn test_canceling_alarm() {
 #[test]
 #[cfg(not(target_os = "redox"))]
 fn test_symlinkat() {
-    let _m = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m = crate::CWD_LOCK.read();
 
     let tempdir = tempdir().unwrap();
 
@@ -883,7 +883,7 @@ fn test_linkat_newdirfd_none() {
 #[test]
 #[cfg(not(any(target_os = "ios", target_os = "macos", target_os = "redox")))]
 fn test_linkat_no_follow_symlink() {
-    let _m = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m = crate::CWD_LOCK.read();
 
     let tempdir = tempdir().unwrap();
     let oldfilename = "foo.txt";
@@ -920,7 +920,7 @@ fn test_linkat_no_follow_symlink() {
 #[test]
 #[cfg(not(target_os = "redox"))]
 fn test_linkat_follow_symlink() {
-    let _m = crate::CWD_LOCK.read().expect("Mutex got poisoned by another test");
+    let _m = crate::CWD_LOCK.read();
 
     let tempdir = tempdir().unwrap();
     let oldfilename = "foo.txt";