Simplify thread blocking tests

src/tools/miri/tests/fail-dep/libc/eventfd_block_read_twice.rs

@@ -23,7 +23,6 @@ fn main() {
     let fd = unsafe { libc::eventfd(0, flags) };
 
     let thread1 = thread::spawn(move || {
-        thread::park();
         let mut buf: [u8; 8] = [0; 8];
         // This read will block initially.
         let res: i64 = unsafe { libc::read(fd, buf.as_mut_ptr().cast(), 8).try_into().unwrap() };
@@ -33,7 +32,6 @@ fn main() {
     });
 
     let thread2 = thread::spawn(move || {
-        thread::park();
         let mut buf: [u8; 8] = [0; 8];
         // This read will block initially, then get unblocked by thread3, then get blocked again
         // because the `read` in thread1 executes first and set the counter to 0 again.
@@ -45,7 +43,6 @@ fn main() {
     });
 
     let thread3 = thread::spawn(move || {
-        thread::park();
         let sized_8_data = 1_u64.to_ne_bytes();
         // Write 1 to the counter, so both thread1 and thread2 will unblock.
         let res: i64 = unsafe {
@@ -55,10 +52,6 @@ fn main() {
         assert_eq!(res, 8);
     });
 
-    thread1.thread().unpark();
-    thread2.thread().unpark();
-    thread3.thread().unpark();
-
     thread1.join().unwrap();
     thread2.join().unwrap();
     thread3.join().unwrap();

src/tools/miri/tests/fail-dep/libc/eventfd_block_write_twice.rs

@@ -28,7 +28,6 @@ fn main() {
     assert_eq!(res, 8);
 
     let thread1 = thread::spawn(move || {
-        thread::park();
         let sized_8_data = (u64::MAX - 1).to_ne_bytes();
         let res: i64 = unsafe {
             libc::write(fd, sized_8_data.as_ptr() as *const libc::c_void, 8).try_into().unwrap()
@@ -38,7 +37,6 @@ fn main() {
     });
 
     let thread2 = thread::spawn(move || {
-        thread::park();
         let sized_8_data = (u64::MAX - 1).to_ne_bytes();
         // Write u64::MAX - 1, so the all subsequent write will block.
         let res: i64 = unsafe {
@@ -52,7 +50,6 @@ fn main() {
     });
 
     let thread3 = thread::spawn(move || {
-        thread::park();
         let mut buf: [u8; 8] = [0; 8];
         // This will unblock both `write` in thread1 and thread2.
         let res: i64 = unsafe { libc::read(fd, buf.as_mut_ptr().cast(), 8).try_into().unwrap() };
@@ -61,10 +58,6 @@ fn main() {
         assert_eq!(counter, (u64::MAX - 1));
     });
 
-    thread1.thread().unpark();
-    thread2.thread().unpark();
-    thread3.thread().unpark();
-
     thread1.join().unwrap();
     thread2.join().unwrap();
     thread3.join().unwrap();

src/tools/miri/tests/fail-dep/libc/libc_epoll_block_two_thread.rs

@@ -5,7 +5,6 @@
 //@error-in-other-file: deadlock
 
 use std::convert::TryInto;
-use std::thread;
 use std::thread::spawn;
 
 // Using `as` cast since `EPOLLET` wraps around
@@ -41,10 +40,10 @@ fn check_epoll_wait<const N: usize>(
 
 // Test if only one thread is unblocked if multiple threads blocked on same epfd.
 // Expected execution:
-// 1. Thread 2 blocks.
-// 2. Thread 3 blocks.
-// 3. Thread 1 unblocks thread 3.
-// 4. Thread 2 deadlocks.
+// 1. Thread 1 blocks.
+// 2. Thread 2 blocks.
+// 3. Thread 3 unblocks thread 2.
+// 4. Thread 1 deadlocks.
 fn main() {
     // Create an epoll instance.
     let epfd = unsafe { libc::epoll_create1(0) };
@@ -65,31 +64,22 @@ fn main() {
     let expected_value = fds[0] as u64;
     check_epoll_wait::<1>(epfd, &[(expected_event, expected_value)], 0);
 
+    let expected_event = u32::try_from(libc::EPOLLIN | libc::EPOLLOUT).unwrap();
+    let expected_value = fds[0] as u64;
     let thread1 = spawn(move || {
-        thread::park();
+        check_epoll_wait::<1>(epfd, &[(expected_event, expected_value)], -1);
+        //~^ERROR: deadlocked
+    });
+    let thread2 = spawn(move || {
+        check_epoll_wait::<1>(epfd, &[(expected_event, expected_value)], -1);
+    });
+
+    let thread3 = spawn(move || {
         let data = "abcde".as_bytes().as_ptr();
         let res = unsafe { libc::write(fds[1], data as *const libc::c_void, 5) };
         assert_eq!(res, 5);
     });
 
-    let expected_event = u32::try_from(libc::EPOLLIN | libc::EPOLLOUT).unwrap();
-    let expected_value = fds[0] as u64;
-    let thread2 = spawn(move || {
-        thread::park();
-        check_epoll_wait::<1>(epfd, &[(expected_event, expected_value)], -1);
-        //~^ERROR: deadlocked
-    });
-    let thread3 = spawn(move || {
-        thread::park();
-        check_epoll_wait::<1>(epfd, &[(expected_event, expected_value)], -1);
-    });
-
-    thread2.thread().unpark();
-    thread::yield_now();
-    thread3.thread().unpark();
-    thread::yield_now();
-    thread1.thread().unpark();
-
     thread1.join().unwrap();
     thread2.join().unwrap();
     thread3.join().unwrap();

src/tools/miri/tests/fail-dep/libc/libc_epoll_block_two_thread.stderr

@@ -1,3 +1,9 @@
+error: deadlock: the evaluated program deadlocked
+   |
+   = note: the evaluated program deadlocked
+   = note: (no span available)
+   = note: BACKTRACE on thread `unnamed-ID`:
+
 error: deadlock: the evaluated program deadlocked
   --> RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
    |
@@ -11,15 +17,9 @@ LL |         let ret = unsafe { libc::pthread_join(id, ptr::null_mut()) };
 note: inside `main`
   --> tests/fail-dep/libc/libc_epoll_block_two_thread.rs:LL:CC
    |
-LL |     thread2.join().unwrap();
+LL |     thread1.join().unwrap();
    |     ^^^^^^^^^^^^^^
 
-error: deadlock: the evaluated program deadlocked
-   |
-   = note: the evaluated program deadlocked
-   = note: (no span available)
-   = note: BACKTRACE on thread `unnamed-ID`:
-
 error: deadlock: the evaluated program deadlocked
   --> tests/fail-dep/libc/libc_epoll_block_two_thread.rs:LL:CC
    |

src/tools/miri/tests/pass-dep/libc/libc-eventfd.rs

@@ -197,7 +197,6 @@ fn test_two_threads_blocked_on_eventfd() {
     assert_eq!(res, 8);
 
     let thread1 = thread::spawn(move || {
-        thread::park();
         let sized_8_data = 1_u64.to_ne_bytes();
         let res: i64 = unsafe {
             libc::write(fd, sized_8_data.as_ptr() as *const libc::c_void, 8).try_into().unwrap()
@@ -207,7 +206,6 @@ fn test_two_threads_blocked_on_eventfd() {
     });
 
     let thread2 = thread::spawn(move || {
-        thread::park();
         let sized_8_data = 1_u64.to_ne_bytes();
         let res: i64 = unsafe {
             libc::write(fd, sized_8_data.as_ptr() as *const libc::c_void, 8).try_into().unwrap()
@@ -217,7 +215,6 @@ fn test_two_threads_blocked_on_eventfd() {
     });
 
     let thread3 = thread::spawn(move || {
-        thread::park();
         let mut buf: [u8; 8] = [0; 8];
         // This will unblock previously blocked eventfd read.
         let res = read_bytes(fd, &mut buf);
@@ -227,10 +224,6 @@ fn test_two_threads_blocked_on_eventfd() {
         assert_eq!(counter, (u64::MAX - 1));
     });
 
-    thread1.thread().unpark();
-    thread2.thread().unpark();
-    thread3.thread().unpark();
-
     thread1.join().unwrap();
     thread2.join().unwrap();
     thread3.join().unwrap();