[PATCH 1/2] ipc: WARN if trying to remove ipc object which is absent

[Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>]

Lets produce a warning if we trying to remove non-existing
IPC object from IPC namespace kht/idr structures.

This allows to catch possible bugs when ipc_rmid() function was
called with inconsistent struct ipc_ids*, struct kern_ipc_perm*
arguments.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Alexander Mikhalitsyn <alexander@mihalicyn.com>
Cc: stable@vger.kernel.org
Co-developed-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
---
 ipc/util.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ipc/util.c b/ipc/util.c
index 0027e47626b7..b28003c653d1 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -447,8 +447,8 @@ static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
 static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
 {
 	if (ipcp->key != IPC_PRIVATE)
-		rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode,
-				       ipc_kht_params);
+		WARN_ON_ONCE(rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode,
+				       ipc_kht_params));
 }
 
 /**
@@ -498,7 +498,7 @@ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
 {
 	int idx = ipcid_to_idx(ipcp->id);
 
-	idr_remove(&ids->ipcs_idr, idx);
+	WARN_ON_ONCE(idr_remove(&ids->ipcs_idr, idx) != ipcp);
 	ipc_kht_remove(ids, ipcp);
 	ids->in_use--;
 	ipcp->deleted = true;
-- 
2.31.1