From 141adeb4933bf3ffe1d4a69f51f6055765fdae86 Mon Sep 17 00:00:00 2001
From: Mohsen Zohrevandi <mohsen.zohrevandi@fortanix.com>
Date: Tue, 21 Jul 2020 11:08:37 -0700
Subject: Fix sync_once_cell_does_not_leak_partially_constructed_boxes

Spinning multiple threads in this test causes a deadlock in
SGX where thread scheduling is not preemptive.
---
 src/libstd/lazy.rs | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'src/libstd')

diff --git a/src/libstd/lazy.rs b/src/libstd/lazy.rs
index 86e1cfae582..1705a4f77c5 100644
--- a/src/libstd/lazy.rs
+++ b/src/libstd/lazy.rs
@@ -827,6 +827,8 @@ mod tests {
                         tx.send(msg).unwrap();
                         break;
                     }
+                    #[cfg(target_env = "sgx")]
+                    crate::thread::yield_now();
                 }
             });
         }
-- 
cgit 1.4.1-3-g733a5


From 7a5d3abfb1aa3a38e0b3b3508c760fc8e712226c Mon Sep 17 00:00:00 2001
From: Tomasz Miąsko <tomasz.miasko@gmail.com>
Date: Mon, 6 Jul 2020 00:00:00 +0000
Subject: Avoid writes without any data in `Write::write_all_vectored`

Previously, when non-empty sequence of empty IoSlices have been provided
to `Write::write_all_vectored`, the buffers would be written as is with
`Write::write_vectored` and subsequently the return value `Ok(0)` would
be misinterpreted as an error.

Avoid writes without any data by advancing the buffers first. This
matches the documented behaviour of `Write::write_all_vectored`
and is analogous to what happens in `Write::write_all`.
---
 src/libstd/io/mod.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'src/libstd')

diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 797318d95b7..9eb54c2cc00 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -251,7 +251,6 @@
 
 use crate::cmp;
 use crate::fmt;
-use crate::mem;
 use crate::memchr;
 use crate::ops::{Deref, DerefMut};
 use crate::ptr;
@@ -1435,12 +1434,15 @@ pub trait Write {
     /// ```
     #[unstable(feature = "write_all_vectored", issue = "70436")]
     fn write_all_vectored(&mut self, mut bufs: &mut [IoSlice<'_>]) -> Result<()> {
+        // Guarantee that bufs is empty if it contains no data,
+        // to avoid calling write_vectored if there is no data to be written.
+        bufs = IoSlice::advance(bufs, 0);
         while !bufs.is_empty() {
             match self.write_vectored(bufs) {
                 Ok(0) => {
                     return Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"));
                 }
-                Ok(n) => bufs = IoSlice::advance(mem::take(&mut bufs), n),
+                Ok(n) => bufs = IoSlice::advance(bufs, n),
                 Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
                 Err(e) => return Err(e),
             }
@@ -2958,6 +2960,7 @@ mod tests {
         #[rustfmt::skip] // Becomes unreadable otherwise.
         let tests: Vec<(_, &'static [u8])> = vec![
             (vec![], &[]),
+            (vec![IoSlice::new(&[]), IoSlice::new(&[])], &[]),
             (vec![IoSlice::new(&[1])], &[1]),
             (vec![IoSlice::new(&[1, 2])], &[1, 2]),
             (vec![IoSlice::new(&[1, 2, 3])], &[1, 2, 3]),
-- 
cgit 1.4.1-3-g733a5