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Fix semaphore data races 

PiperOrigin-RevId: 202371908
Change-Id: I72603b1d321878cae6404987c49e64732b676331
This commit is contained in:
Fabricio Voznika 2018-06-27 14:40:37 -07:00 committed by Shentubot
parent 99afc982f1
commit 6b6852bceb
1 changed files with 8 additions and 4 deletions
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12
pkg/sentry/kernel/semaphore/semaphore.go
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@ -118,6 +118,9 @@ func (r *Registry) FindOrCreate(ctx context.Context, key, nsems int32, mode linu
if !private {
// Look up an existing semaphore.
if set := r.findByKey(key); set != nil {
set.mu.Lock()
defer set.mu.Unlock()
// Check that caller can access semaphore set.
creds := auth.CredentialsFromContext(ctx)
if !set.checkPerms(creds, fs.PermsFromMode(mode)) {
@ -170,6 +173,9 @@ func (r *Registry) RemoveID(id int32, creds *auth.Credentials) error {
return syserror.EINVAL
}
set.mu.Lock()
defer set.mu.Unlock()
// "The effective user ID of the calling process must match the creator or
// owner of the semaphore set, or the caller must be privileged."
if !set.checkCredentials(creds) && !set.checkCapability(creds) {
@ -444,11 +450,9 @@ func (s *Set) checkPerms(creds *auth.Credentials, reqPerms fs.PermMask) bool {
return s.checkCapability(creds)
}
// destroy destroys the set. Caller must hold 's.mu'.
func (s *Set) destroy() {
s.mu.Lock()
defer s.mu.Unlock()
// Notify all waiters. Tney will fail on the next attempt to execute
// Notify all waiters. They will fail on the next attempt to execute
// operations and return error.
s.dead = true
for _, s := range s.sems {