From 5774ed014f02120db9a6945a1ecebeb97c2acccb Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Fri, 29 Jul 2011 03:55:31 +0400 Subject: shm: handle separate PID namespaces case shm_try_destroy_orphaned() and shm_try_destroy_current() didn't handle the case of separate PID namespaces, but a single IPC namespace. If there are tasks with the same PID values using the same shmem object, the wrong destroy decision could be reached. On shm segment creation store the pointer to the creator task in shmid_kernel->shm_creator field and zero it on task exit. Then use the ->shm_creator insread of shm_cprid in both functions. As shmid_kernel object is already locked at this stage, no additional locking is needed. Signed-off-by: Vasiliy Kulikov Acked-by: Serge Hallyn Signed-off-by: Linus Torvalds --- include/linux/shm.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/shm.h') diff --git a/include/linux/shm.h b/include/linux/shm.h index 7d27ffd..92808b8 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 */ -- cgit v1.1