The patch titled
Subject: ipc,shm: move BUG_ON check into shm_lock
has been added to the -mm tree. Its filename is
ipcshm-move-bug_on-check-into-shm_lock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ipcshm-move-bug_on-check-into-shm_lock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ipcshm-move-bug_on-check-into-shm_lock.patch
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------------------------------------------------------
From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Subject: 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.
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/shm.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff -puN ipc/shm.c~ipcshm-move-bug_on-check-into-shm_lock ipc/shm.c
--- a/ipc/shm.c~ipcshm-move-bug_on-check-into-shm_lock
+++ a/ipc/shm.c
@@ -155,8 +155,14 @@ static inline struct shmid_kernel *shm_l
{
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 shm_destroy(),
+ * either way, the ID is busted.
+ */
+ BUG();
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_stru
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_str
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);
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxx are
mm-hugetlb-document-the-reserve-map-region-tracking-routines.patch
mm-hugetlb-compute-return-the-number-of-regions-added-by-region_add.patch
mm-hugetlb-handle-races-in-alloc_huge_page-and-hugetlb_reserve_pages.patch
mm-hugetlb-handle-races-in-alloc_huge_page-and-hugetlb_reserve_pages-v4.patch
ipcshm-move-bug_on-check-into-shm_lock.patch
ipcmsg-provide-barrier-pairings-for-lockless-receive.patch
ipc-rename-ipc_obtain_object.patch
ipcsysv-make-return-eidrm-when-racing-with-rmid-consistent.patch
ipcsysv-return-einval-upon-incorrect-id-seqnum.patch
linux-next.patch
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