2012-08-03 12:14:25

by microcai

[permalink] [raw]
Subject: [PATCH] [ipc/shm] make shmget with IPC_PRIVATE initially created with SHM_DEST

The problem is SysV SHM is that , it will cause kernel resource leak.
Initailly set shm mode to SHM_DEST when create with key_t IPC_PRIVATE,
then the resource leak is fixed.

If program want the shmid live longer, they will probably use non
IPC_PRIVATE nor call shmctl that remove SHM_DEST bit.
---
ipc/shm.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/ipc/shm.c b/ipc/shm.c
index 41c1285..1abc031 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -480,6 +480,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)

shp->shm_perm.key = key;
shp->shm_perm.mode = (shmflg & S_IRWXUGO);
+ if(key == IPC_PRIVATE)
+ shp->shm_perm.mode |= SHM_DEST;
shp->mlock_user = NULL;

shp->shm_perm.security = NULL;
--
1.7.8.6