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Add assertions to verify that grants are unmapped
Fix grant unmapping in exec and exit, thus fixing some crashes without network cards
This commit is contained in:
Jeremy Soller 2016-12-06 14:47:05 -07:00
parent 7ee0ea3c86
commit 31d62f9272
5 changed files with 61 additions and 8 deletions
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31
kernel/syscall/process.rs
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@ -511,10 +511,22 @@ pub fn exec(path: &[u8], arg_ptrs: &[[usize; 2]]) -> Result<usize> {
// Unmap previous image, heap, grants, stack, and tls
context.image.clear();
drop(context.heap.take());
context.grants = Arc::new(Mutex::new(Vec::new()));
drop(context.stack.take());
drop(context.tls.take());
let mut unmap_grants = Vec::new();
// FIXME: Looks like a race condition.
// Is it possible for Arc::strong_count to return 1 to two contexts that exit at the
// same time, or return 2 to both, thus either double freeing or leaking the grants?
if Arc::strong_count(&context.grants) == 1 {
mem::swap(context.grants.lock().deref_mut(), &mut unmap_grants);
}
context.grants = Arc::new(Mutex::new(Vec::new()));
for grant in unmap_grants {
grant.unmap();
}
if stat.st_mode & syscall::flag::MODE_SETUID == syscall::flag::MODE_SETUID {
context.euid = stat.st_uid;
}
@ -753,7 +765,10 @@ pub fn exit(status: usize) -> ! {
let mut close_files = Vec::new();
let (pid, ppid) = {
let mut context = context_lock.write();
if Arc::strong_count(&context.files) == 1 { // FIXME: Looks like a race condition.
// FIXME: Looks like a race condition.
// Is it possible for Arc::strong_count to return 1 to two contexts that exit at the
// same time, or return 2 to both, thus either double closing or leaking the files?
if Arc::strong_count(&context.files) == 1 {
mem::swap(context.files.lock().deref_mut(), &mut close_files);
}
context.files = Arc::new(Mutex::new(Vec::new()));
@ -796,8 +811,20 @@ pub fn exit(status: usize) -> ! {
drop(context.heap.take());
drop(context.stack.take());
drop(context.tls.take());
let mut unmap_grants = Vec::new();
// FIXME: Looks like a race condition.
// Is it possible for Arc::strong_count to return 1 to two contexts that exit at the
// same time, or return 2 to both, thus either double freeing or leaking the grants?
if Arc::strong_count(&context.grants) == 1 {
mem::swap(context.grants.lock().deref_mut(), &mut unmap_grants);
}
context.grants = Arc::new(Mutex::new(Vec::new()));
for grant in unmap_grants {
grant.unmap();
}
let vfork = context.vfork;
context.vfork = false;