diff options
| -rw-r--r-- | include/linux/shm.h | 3 | ||||
| -rw-r--r-- | ipc/shm.c | 27 |
2 files changed, 23 insertions, 7 deletions
diff --git a/include/linux/shm.h b/include/linux/shm.h index 7d27ffde019..92808b86703 100644 --- a/include/linux/shm.h +++ b/include/linux/shm.h @@ -95,6 +95,9 @@ struct shmid_kernel /* private to the kernel */ pid_t shm_cprid; pid_t shm_lprid; struct user_struct *mlock_user; + + /* The task created the shm object. NULL if the task is dead. */ + struct task_struct *shm_creator; }; /* shm_mode upper byte flags */ diff --git a/ipc/shm.c b/ipc/shm.c index 3f5b14365f3..fdaf8be65b7 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -239,7 +239,23 @@ static int shm_try_destroy_current(int id, void *p, void *data) if (IS_ERR(shp)) return 0; - if (shp->shm_cprid != task_tgid_vnr(current)) { + if (shp->shm_creator != current) { + shm_unlock(shp); + return 0; + } + + /* + * Mark it as orphaned to destroy the segment when + * kernel.shm_rmid_forced is changed. + * It is noop if the following shm_may_destroy() returns true. + */ + shp->shm_creator = NULL; + + /* + * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID + * is not set, it shouldn't be deleted here. + */ + if (!ns->shm_rmid_forced) { shm_unlock(shp); return 0; } @@ -255,7 +271,6 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data) { struct ipc_namespace *ns = data; struct shmid_kernel *shp = shm_lock(ns, id); - struct task_struct *task; if (IS_ERR(shp)) return 0; @@ -263,11 +278,8 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data) /* * We want to destroy segments without users and with already * exit'ed originating process. - * - * XXX: the originating process may exist in another pid namespace. */ - task = find_task_by_vpid(shp->shm_cprid); - if (task != NULL) { + if (shp->shm_creator != NULL) { shm_unlock(shp); return 0; } @@ -295,7 +307,7 @@ void exit_shm(struct task_struct *task) if (!nsp) return; ns = nsp->ipc_ns; - if (!ns || !ns->shm_rmid_forced) + if (!ns) return; /* Destroy all already created segments, but not mapped yet */ @@ -494,6 +506,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) shp->shm_segsz = size; shp->shm_nattch = 0; shp->shm_file = file; + shp->shm_creator = current; /* * shmid gets reported as "inode#" in /proc/pid/maps. * proc-ps tools use this. Changing this will break them. |