Pass WeakFileDescriptionRef to the callback to check if the file description is closed

Author: tiif

src/shims/unix/fd.rs

@@ -296,6 +296,12 @@ impl WeakFileDescriptionRef {
     }
 }
 
+impl VisitProvenance for WeakFileDescriptionRef {
+    fn visit_provenance(&self, _visit: &mut VisitWith<'_>) {
+        // All our WeakFileDescriptionRef do not have any tags.
+    }
+}
+
 /// A unique id for file descriptions. While we could use the address, considering that
 /// is definitely unique, the address would expose interpreter internal state when used
 /// for sorting things. So instead we generate a unique id per file description that stays

src/shims/unix/linux/epoll.rs

@@ -4,7 +4,7 @@ use std::io;
 use std::rc::{Rc, Weak};
 use std::time::Duration;
 
-use crate::shims::unix::fd::FdId;
+use crate::shims::unix::fd::{FdId, WeakFileDescriptionRef};
 use crate::shims::unix::*;
 use crate::*;
 
@@ -402,6 +402,10 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             this.write_scalar(Scalar::from_i32(result_value), &dest)?;
             return Ok(());
         };
+        // Create a weak ref of epfd and pass it to callback so we will make sure that epfd
+        // is not close after the thread unblocks.
+        let weak_epfd = epfd.downgrade();
+
         let mut binding = epfd.borrow_mut();
         let epoll_file_description = &mut binding
             .downcast_mut::<Epoll>()
@@ -424,11 +428,12 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                     callback!(
                         @capture<'tcx> {
                             epfd_value: i32,
+                            weak_epfd: WeakFileDescriptionRef,
                             dest: MPlaceTy<'tcx>,
                             event: MPlaceTy<'tcx>,
                         }
                         @unblock = |this| {
-                            this.blocking_epoll_callback(epfd_value, &dest, &event)?;
+                            this.blocking_epoll_callback(epfd_value, weak_epfd, &dest, &event)?;
                             Ok(())
                         }
                         @timeout = |this| {
@@ -440,7 +445,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             }
         } else {
             // Non-blocking with notification returned.
-            this.blocking_epoll_callback(epfd_value, &dest, &event)?;
+            this.blocking_epoll_callback(epfd_value, weak_epfd, &dest, &event)?;
             return Ok(());
         }
 
@@ -450,17 +455,17 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
     /// Callback function after epoll_wait unblocks
     fn blocking_epoll_callback(
         &mut self,
-        epfd: i32,
+        epfd_value: i32,
+        weak_epfd: WeakFileDescriptionRef,
         dest: &MPlaceTy<'tcx>,
         event: &MPlaceTy<'tcx>,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        let Some(epfd) = this.machine.fds.get_ref(epfd) else {
-            let result_value = this.fd_not_found()?;
-            this.write_scalar(Scalar::from_i32(result_value), dest)?;
-            return Ok(());
+        let Some(epfd) = weak_epfd.upgrade() else {
+            throw_unsup_format!("epoll file descriptor {epfd_value} is closed while blocking.")
         };
+
         let mut binding = epfd.borrow_mut();
         let epoll_file_description = &mut binding
             .downcast_mut::<Epoll>()