diff options
Diffstat (limited to 'ipc/sem.c')
| -rw-r--r-- | ipc/sem.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index cddd5b5fde51..b3757ea0694b 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -92,7 +92,14 @@ /* One semaphore structure for each semaphore in the system. */ struct sem { int semval; /* current value */ - int sempid; /* pid of last operation */ + /* + * PID of the process that last modified the semaphore. For + * Linux, specifically these are: + * - semop + * - semctl, via SETVAL and SETALL. + * - at task exit when performing undo adjustments (see exit_sem). + */ + int sempid; spinlock_t lock; /* spinlock for fine-grained semtimedop */ struct list_head pending_alter; /* pending single-sop operations */ /* that alter the semaphore */ @@ -1444,8 +1451,10 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, goto out_unlock; } - for (i = 0; i < nsems; i++) + for (i = 0; i < nsems; i++) { sma->sem_base[i].semval = sem_io[i]; + sma->sem_base[i].sempid = task_tgid_vnr(current); + } ipc_assert_locked_object(&sma->sem_perm); list_for_each_entry(un, &sma->list_id, list_id) { |