diff options
Diffstat (limited to 'src/libstd/sys')
| -rw-r--r-- | src/libstd/sys/unix/thread.rs | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/src/libstd/sys/unix/thread.rs b/src/libstd/sys/unix/thread.rs index b9ec0d4a403..6064b55489e 100644 --- a/src/libstd/sys/unix/thread.rs +++ b/src/libstd/sys/unix/thread.rs @@ -223,8 +223,8 @@ pub mod guard { #[cfg_attr(test, allow(dead_code))] pub mod guard { use libc; - use libc::{mmap, munmap}; - use libc::{PROT_NONE, MAP_PRIVATE, MAP_ANON, MAP_FAILED, MAP_FIXED}; + use libc::mmap; + use libc::{PROT_NONE, PROT_READ, PROT_WRITE, MAP_PRIVATE, MAP_ANON, MAP_FAILED, MAP_FIXED}; use ops::Range; use sys::os; @@ -347,9 +347,19 @@ pub mod guard { pub unsafe fn deinit() { if !cfg!(target_os = "linux") { if let Some(stackaddr) = get_stack_start_aligned() { - // Undo the guard page mapping. - if munmap(stackaddr, PAGE_SIZE) != 0 { - panic!("unable to deallocate the guard page"); + // Remove the protection on the guard page. + // FIXME: we cannot unmap the page, because when we mmap() + // above it may be already mapped by the OS, which we can't + // detect from mmap()'s return value. If we unmap this page, + // it will lead to failure growing stack size on platforms like + // macOS. Instead, just restore the page to a writable state. + // This ain't Linux, so we probably don't need to care about + // execstack. + let result = mmap(stackaddr, PAGE_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON | MAP_FIXED, -1, 0); + + if result != stackaddr || result == MAP_FAILED { + panic!("unable to reset the guard page"); } } } |