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| author | Davidlohr Bueso <dave@stgolabs.net> | 2015-06-05 15:03:52 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2015-06-05 15:03:52 +1000 |
| commit | f1c46c11665ebea83ccf8b43744a73926d8b3187 (patch) | |
| tree | 22935717554be2407a032c22df735dfdaaa6447c | |
| parent | 219248982757dc789c48eccebe2237e3fe6a7cde (diff) | |
| download | linux-next-f1c46c11665ebea83ccf8b43744a73926d8b3187.tar.gz | |
ipc,shm: move BUG_ON check into shm_lock
Upon every shm_lock call, we BUG_ON if an error was returned, indicating
racing either in idr or in RMID. Move this logic into the locking.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | ipc/shm.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 6d767071c3673d..3152dea8dbc80d 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -155,8 +155,14 @@ static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) { struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); - if (IS_ERR(ipcp)) + if (IS_ERR(ipcp)) { + /* + * We raced in the idr lookup or with RMID, + * either way, the ID is busted. + */ + BUG_ON(1); return (struct shmid_kernel *)ipcp; + } return container_of(ipcp, struct shmid_kernel, shm_perm); } @@ -191,7 +197,6 @@ static void shm_open(struct vm_area_struct *vma) struct shmid_kernel *shp; shp = shm_lock(sfd->ns, sfd->id); - BUG_ON(IS_ERR(shp)); shp->shm_atim = get_seconds(); shp->shm_lprid = task_tgid_vnr(current); shp->shm_nattch++; @@ -258,7 +263,6 @@ static void shm_close(struct vm_area_struct *vma) down_write(&shm_ids(ns).rwsem); /* remove from the list of attaches of the shm segment */ shp = shm_lock(ns, sfd->id); - BUG_ON(IS_ERR(shp)); shp->shm_lprid = task_tgid_vnr(current); shp->shm_dtim = get_seconds(); shp->shm_nattch--; @@ -1191,7 +1195,6 @@ out_fput: out_nattch: down_write(&shm_ids(ns).rwsem); shp = shm_lock(ns, shmid); - BUG_ON(IS_ERR(shp)); shp->shm_nattch--; if (shm_may_destroy(ns, shp)) shm_destroy(ns, shp); |