review comments

Author: nia-e

src/alloc/isolated_alloc.rs

@@ -273,9 +273,9 @@ impl IsolatedAlloc {
             self.page_ptrs.clone().into_iter().map(|p| p.expose_provenance()).collect();
         for (ptr, size) in &self.huge_ptrs {
             for i in 0..size / self.page_size {
-                pages.push(unsafe { ptr.add(i * self.page_size).expose_provenance() });
+                pages.push(ptr.expose_provenance().strict_add(i * self.page_size));
             }
-        });
+        }
         pages
     }
 }

src/bin/miri.rs

@@ -798,7 +798,11 @@ fn main() {
     #[cfg(target_os = "linux")]
     if !miri_config.native_lib.is_empty() && !miri_config.force_old_native_lib {
         // FIXME: This should display a diagnostic / warning on error
-        // SAFETY: No other threads have spawned yet
+        // SAFETY: If any other threads exist at this point (e.g. for the ctrlc
+        // handler), they will not interact with anything on the main rustc/Miri
+        // thread in an async-signal-unsafe way such as by accessing shared
+        // semaphores, etc.; the handler only calls `sleep()` and `exit()`, which
+        // are async-signal-safe, and accessing atomics is also
         let _ = unsafe { miri::init_sv() };
     }
     run_compiler_and_exit(

src/shims/trace/child.rs

@@ -5,10 +5,10 @@ use ipc_channel::ipc;
 use nix::sys::{ptrace, signal};
 use nix::unistd;
 
-use crate::alloc::isolated_alloc::IsolatedAlloc;
 use super::messages::{Confirmation, MemEvents, TraceRequest};
 use super::parent::{ChildListener, sv_loop};
 use super::{FAKE_STACK_SIZE, StartFfiInfo};
+use crate::alloc::isolated_alloc::IsolatedAlloc;
 
 static SUPERVISOR: std::sync::Mutex<Option<Supervisor>> = std::sync::Mutex::new(None);
 
@@ -135,7 +135,7 @@ impl Supervisor {
 /// receiving back events through `get_events`.
 ///
 /// # Safety
-/// Only a single OS thread must exist in the process when calling this.
+/// The invariants for `fork()` must be upheld by the caller.
 pub unsafe fn init_sv() -> Result<(), SvInitError> {
     // On Linux, this will check whether ptrace is fully disabled by the Yama module.
     // If Yama isn't running or we're not on Linux, we'll still error later, but