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| author | Davidlohr Bueso <dave@stgolabs.net> | 2015-06-30 23:58:36 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-07-01 04:44:58 +0200 |
| commit | c5c8975b2eb4eb7604e8ce4f762987f56d2a96a2 (patch) | |
| tree | 9f21ef2539c3c0110dde47e1fc6b56c50da8b507 | |
| parent | ipc/util.c: use kvfree() in ipc_rcu_free() (diff) | |
| download | linux-c5c8975b2eb4eb7604e8ce4f762987f56d2a96a2.tar.xz linux-c5c8975b2eb4eb7604e8ce4f762987f56d2a96a2.zip | |
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 shm_destroy. Move this logic into the locking.
[akpm@linux-foundation.org: simplify code]
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | ipc/shm.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 6d767071c367..bd9c91f433c1 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -155,8 +155,11 @@ 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)) - return (struct shmid_kernel *)ipcp; + /* + * We raced in the idr lookup or with shm_destroy(). Either way, the + * ID is busted. + */ + BUG_ON(IS_ERR(ipcp)); return container_of(ipcp, struct shmid_kernel, shm_perm); } @@ -191,7 +194,6 @@ 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 +260,6 @@ 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 +1192,6 @@ 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); |