From 2cd648c110b5570c3280bd645797658cabbe5f5c Mon Sep 17 00:00:00 2001 From: Manfred Spraul Date: Wed, 12 Jul 2017 14:34:44 -0700 Subject: [PATCH] include/linux/sem.h: correctly document sem_ctime sem_ctime is initialized to the semget() time and then updated at every semctl() that changes the array. Thus it does not represent the time of the last change. Especially, semop() calls are only stored in sem_otime, not in sem_ctime. This is already described in ipc/sem.c, I just overlooked that there is a comment in include/linux/sem.h and man semctl(2) as well. So: Correct wrong comments. Link: http://lkml.kernel.org/r/20170515171912.6298-4-manfred@colorfullife.com Signed-off-by: Manfred Spraul Cc: Kees Cook Cc: <1vier1@web.de> Cc: Davidlohr Bueso Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Fabian Frederick Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sem.h | 2 +- include/uapi/linux/sem.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/sem.h b/include/linux/sem.h index 9db1409..be5cf2e 100644 --- a/include/linux/sem.h +++ b/include/linux/sem.h @@ -30,7 +30,7 @@ struct sem { /* One sem_array data structure for each set of semaphores in the system. */ struct sem_array { struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */ - time_t sem_ctime; /* last change time */ + time_t sem_ctime; /* create/last semctl() time */ struct list_head pending_alter; /* pending operations */ /* that alter the array */ struct list_head pending_const; /* pending complex operations */ diff --git a/include/uapi/linux/sem.h b/include/uapi/linux/sem.h index dd73b90..67eb903 100644 --- a/include/uapi/linux/sem.h +++ b/include/uapi/linux/sem.h @@ -23,7 +23,7 @@ struct semid_ds { struct ipc_perm sem_perm; /* permissions .. see ipc.h */ __kernel_time_t sem_otime; /* last semop time */ - __kernel_time_t sem_ctime; /* last change time */ + __kernel_time_t sem_ctime; /* create/last semctl() time */ struct sem *sem_base; /* ptr to first semaphore in array */ struct sem_queue *sem_pending; /* pending operations to be processed */ struct sem_queue **sem_pending_last; /* last pending operation */ -- 2.7.4